sailboat prop shaft stuffing box

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Repack A Stuffing Box

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Keeping the water on the outside of the boat is essential. Here's how an inboard-powered boat gets a shaft from the inside to the outside.

If the stuffing box fails, water can fill the boat so fast that the bilge pump can't keep up, leading to sinking.

If your boat has inboard power, chances are it has a stuffing box that allows a propeller shaft to penetrate the hull below the waterline without letting water in and flooding the boat. There are three main components to a traditional stuffing box: the stuffing box body, the compression sleeve, and some method of locking the compression sleeve in place. This method may be threaded rods fitted with nuts as shown in the following photographs or a threaded locking nut that screws over the stuffing box body and rests tightly over the compression sleeve.

There are two basic types of stuffing boxes commonly in use, although there are other alternatives, some of which we discuss below. Perhaps the most common type consists of a stuffing box body attached to a special heavy-duty hose (attached to the shaft gland), a compression sleeve into which the stuffing is packed and which screws over the body, and a locking nut that locks the compression sleeve into place.

The second basic type, like that on my boat and to which I'll primarily refer in this article, consists of the body that is attached to the hose and into which the packing is stuffed, and a compression sleeve that compresses the stuffing by tightening the nuts on the bolts protruding from the body.

A PSS shaft seal before fitting. The carbon ring is placed under tension by the rubber bellows against the stainless-steel ring, which is clamped to the shaft. Note the water injection nipple at the top of the carbon ring.

Under the compression sleeve are three or more rounds of packing material. Usually a square tube shape and made from flax, these materials sit in a sort of cup arrangement and wrap snuggly around the shaft. As the packing compression sleeve is tightened, the flax is slightly squeezed outward toward the shaft, lightly gripping the shaft and preventing water from entering the boat.

Adjustments Are Required

When properly adjusted, stuffing boxes are designed to "leak" slightly at two to three drops per minute while the engine is running and the shaft is turning. There should be no dripping when the boat is at rest and the shaft is not spinning.

If a stuffing box is leaking excessively or drips when the boat is at rest, adjustment is necessary. To do this, loosen the locknut (depending on type, this may be the nut threaded around the body or lock washers on the bolts), tighten the adjustment sleeve a little, then retighten the locknut. The stuffing box must never be overtightened as it's designed to leak a little. The water acts as a lubricant and prevents the packing from overheating while the shaft is turning. After you make any adjustments, monitor the stuffing box to ensure all is well; at no point should a packing box get too hot to touch. If you can't leave your hand on the fitting after the engine has run, that's an indication that it's been overtightened and you need to loosen the compression sleeve just a little.

Repacking May Be Necessary

Over time the packing will wear, and no amount of adjustment will prevent more water than desired from entering the boat. When this happens, it's time to change the packing material, which can be purchased from retailers such as Defender or West Marine .

Packing comes in different sizes depending on the size of the shaft; the larger the shaft, the bigger the packing required. As a general rule, shafts up to about 11/2 inches require quarter-inch packing. Any larger, and you'll probably be looking at 3/8 inch.

While packing material is traditionally made of flax, recently it's being made out of other materials. Perhaps the most popular incorporates Teflon, which increases wear resistance while reducing friction on the shaft.

Although it's possible to change the packing with the boat in the water, we recommend against that. Do it with the boat on the hard, especially if this is your first time.

Failure Can Happen

Stuffing box failure when a boat is left unattended at the dock will almost always result in a sinking. The inrush of water is so severe that no bilge pump can keep up with the flow. Bad as it may be with the boat tied to the dock, when the boat is offshore and possibly miles from a safe haven, it can be devastating.

While the exact course of action will be determined to some extent by the boat and type of shaft stuffing box or seal you have, the first thing you'll want to do is stop or at least slow the rate of water coming into the boat. If the boat is under power, shut down the engine. This may sometimes be enough to stop, or reduce, water flow. Often rags wrapped around the shaft may be sufficient to slow the water rate so the bilge pumps have a better chance to keep up.

Failures are not always with the shaft seal or stuffing box itself. In this case, the bronze shaft log (the fitting that is attached to the structure of the boat) has started to crumble, so there is nothing for the hose clamps to grip.

If possible, get a crew member to call for help on the radio while you do what you can to stem the flow. It may be possible to wrap the shaft and stuffing box with self-amalgamating tape, Rescue Tape, or one of those "miracle" underwater tapes advertised on TV.

Some boats have V-drives where the stuffing box is located literally under the engine, making temporary repairs almost impossible.

Failure Points

Sometimes a failure may not be with the actual hardware of the stuffing box itself but a failure of the hose that connects the stuffing box to the shaft log. This short section of hose may be small, but vital to the safety of the boat.

Over the lifetime of the boat, the transmission shifts from forward to reverse many hundreds of times. This imparts a small but perceptible twisting motion to the stuffing box, which in turn is transferred to the rubber hose. If the packing were to run dry by being overtightened, this twisting motion increases significantly, stressing the hose. Often a short length of exhaust hose may be used, but this is incorrect. Hose specially designed to connect the stuffing box to the shaft log will be five-ply, a heavier duty than exhaust hose. This is not a place to save a few bucks. The same goes for hose clamps, which should be nonperforated stainless steel. (To learn more about hose clamps, see " All About Hose Clamps ")

Another potential source of failure is where the water is injected into the stuffing box or dripless seal. (Some stuffing boxes with packing will not have water injection.) The injected water serves two purposes: It keeps the rotating shaft cool and provides lubrication. However, should the injector hose fail in some way, either by coming detached from the nipple on the stuffing box or by developing a leak through a split, two outcomes are possible. Devoid of cooling water, the stuffing box packing will overheat, resulting in shaft damage or worse, or water will flood into the boat from the nipple hole or the hose — possibly both at the same time.

Also, if the stuffing box has water injection for cooling and lubrication, it may be possible for the sleeve that goes into the hose to seize to the shaft due to overheating and twist the hose until it breaches. Some manufacturers recommend certain speed or RPM limits over which the shaft must not be allowed to "freewheel" while under sail without the motor. Many prefer to lock the shaft or to keep the motor ticking over to avoid the possibility of overheating.

Alternatives

Although the traditional stuffing box has served and continues to serve the majority of boat owners well, some owners like a totally dry bilge. Dripless stuffing boxes can allow just that. There are two main types. For example, lip seals like the SureSeal from Tides Marine, feature a seal that has a flexible lip riding on the shaft to keep the water from entering the boat. Another is commonly called a face seal, where a special carbon ring is pressed under tension against a stainless-steel ring clamped to the shaft. Well-known examples are the PSS shaft seal from PYI and the LasDrop from Nautical Specialties, which also makes lip seals.

When correctly installed, both types of seals should last for many years and should allow no water into the boat. And just in case you were wondering if dripless seals were reliable, the LasDrop seals are made for commercial applications in shaft diameters up to 8 inches! All these types of seals rely on seawater for cooling and, in some cases, lubrication. Without it, the seal will have a very short life and fail. Many engines have a take-off port on the wet exhaust for just such a connection. Often, where a traditional stuffing box is replaced with a dripless type, the hose can be transferred from the old to the new.

The maintenance of dripless seals is pretty straightforward. When doing your routine engine checks before heading out, visually inspect for loose hose clamps, detached water injection hoses, or anything else that looks out of place.

Sometimes face seals can leak, frequently due to a tiny piece of dirt trapped between the carbon ring and rotating stainless shaft ring. Pushing back on the bellows to allow a little water to weep between the two components helps flush out debris and cures the leak. Different manufacturers will have specific instructions on maintenance and installation, which should be followed to the letter.

How To Repack A Stuffing Box

1. Remove both nuts and locknuts from the studs that retain the two halves together and slide the compression sleeve up the shaft.

2. Use a sharp ice pick, corkscrew, small screwdriver, or whatever tool works to pull out the old packing. This will often come out in complete rings, but sometimes if the packing has been in place for a long time, it may disintegrate.

3. Here all the packing has been removed, and as you can see, there are five rings in this installation. Yours may have fewer — three is common on smaller shafts.

4. Carefully inspect the shaft for damage and scoring , and clean thoroughly with a rag.

5. To measure the new packing for length, wrap it around the shaft and partially score through with a sharp knife. Do not cut all the way through, or you could damage the shaft. I like to cut the ends at 45 degrees and not straight across, as shown here, as I feel it makes a better seal when pushed into the packing nut.

6. Lay the packing on a suitable block of wood and cut it all the way so that you have individual pieces.

7. Push the new sections of packing into the packing gland. Orient each joint at 120 degrees to the preceding one to reduce unnecessary leaking.

8. Reassemble the components and tighten, but don't overdo it. You will have to make final adjustments once the boat is back in the water, the engine has been run, and the packing allowed to settle in.

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Updating a classic fiberglass cruising yacht.

Re-packing a propeller shaft stuffing box

Summary:  I changed the packing flax material on my propeller stuffing box.  It seems that no one had done this job for several years, so the difficult part was getting the packing nuts loosened up to begin with, and then extracting what I believe was the wrong-sized packing material.  I am glad I completed this work with my boat out of the water.

Introduction

Changing the packing material in a prop shaft stuffing box should be a simple 4-step task: 

• Loosen the packing nut.
• Remove the old packing flax material
• Insert the new lacking flax material
• Re-tighten the packing nut

I did my initial overview/analysis of how my propeller shaft packing gland works in August of 2020 .  That previous post has a discussion of the anatomy of the contraption and which part does what.  I struggled at that point to free the locking nut from the main nut on my stuffing box.  Other Ericson owners were wading through the same challenges . 

Step 1:  Loosen the packing nut

My propeller shaft packing gland started out looking like this, in July 2020: 

While the packing was not leaking, it seemed clear that no previous owner had addressed the stuffing box for some time, and I thought I should figure out the process and change the material. I spent some time cleaning the stuffing box (lots of vinegar, some PB Blaster), and eventually once everything was moving it looked like this: 

I could unscrew the cap nut on the stuffing box, and the locking nut.  

Step 2:  Remove the old packing material 

I went to work removing the wraps of flax material stuffed up inside of the cap nut.  There were three layers of flax and each successive layer took more time to remove.  Here’s what the first one looked like.  

The inner layers took much longer to remove than the lower one.  

For a different task, I had recently purchased an i nexpensive endoscopic camera that can connect to my iPhone via BlueTooth .  For the $36 purchase price it is amazing technology and could peer into the packing nut where neither my eye nor my phone camera could view. 

The arrangement of the stuffing box and transmission is so close that I am left with less than 1” of exposed propeller shaft to work with when the packing nut is slid up.  

I manufactured a ‘flax removal tool’ out of a bent framing nail to gouge out the flax.  The work was so unpleasant that after finishing the job I ordered a special tool that I hope will make the next time easier.  

Harbor Freight also sells inexpensive pick kits that might work well .  

In retrospect I am very glad that I did not attempt this job, at least this first time, with the boat in the water.  It was extremely challenging to remove the old flax and had water been pouring in the stuffing box, it would only have raised my stress level substantially.   The owner’s manual for my boat suggested that I use 1/8th” packing flax, but what I pulled out was much thicker.  It could have been ¼” or even 5/16”: 

Step 3: Insert new packing material

After consultation from other members of the Ericson Owners forum , it seemed like 3/16” was the best choice to re-pack for my 1” propeller shaft.  So that’s what I wound up installing.  

The packing flax manufacturer advises the application of “Syn Tef” lubricant to the packing material.  I dutifully bought a small tube .  It seems like very gummy waterproof grease.  About the consistency of chilled butterscotch syrup.  

I found it helpful to pre-wind the flax into circles to conform to the shaft.  While I imagined the flax would be round like rope or string, it has instead been pre-pressed into a square shape which should help it stick in the packing nut more evenly and retard the water flow.  To measure the right length, the hot tip from the internet is to wind the packing around the shaft and then slice it at the overlap point with a sharp razor blade.  This worked well for me. 

Then I pressed the rings into the nut one by one.  Insert a ring, tighten the nut to seat the ring as far into the nut as possible, repeat.  I tried to offset the butt joints of the flax material but next time I will mark the nut to help me determine what is where.  Without a mark it’s easy to lose track of where the joint in the flax is, as one tightens the nut to seat the ring.

Step 4:  Tighten the packing nut back onto the shaft with the flax rings inserted

With the new greasy flax rings, and the mostly clean packing nut, the reassembly process was easy.  The boat has yet to be in the water to test the replacement, but even if I have something wrong, making an adjustment will be easy compared to the crusty, corroded condition I inherited.  

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Service Your Stuffing Box

• By Steve D Antonio
• Updated: December 4, 2008

prop shaft and packing nut 368

When properly installed and adjusted, a stuffing box will provide hundreds, if not thousands, of hours of reliable, nearly leak-free service.

The keys to a stuffing box’s longevity are twofold. The first and most common cause of chronically leaky stuffing boxes involves the condition of the surface of the propeller shaft directly beneath the packing. If it’s in any way irregular, pitted, or damaged, the packing will be torn up each time the shaft rotates beneath it, which may be as many as 1,500 or 2,000 times per minute. The pitting or damage is often caused by the stuffing box’s oxygen-poor environment. If this is the case, then no amount of repacking-regardless of the type of space-age “leak-proof” material you use-or adjustment will resolve the problem. Two solutions exist: Replace the shaft, or use a longer or shorter stuffing-box hose to move the location of the packing over an undamaged section of shaft.

The second problem, which also results in chronic leakiness, is often caused by a sailor’s response to the first problem: overtightening the nut that contains the flax packing. When the nut is overtightened, the flax overheats, and the wax lubricant melts and runs out. Green or black sticky material under the box means that the stuffing box has overheated; the box must now be disassembled. Clean out all vestiges of packing and wax, then clean the shaft and lightly polish it using 400-grit emery cloth.

Overtightening the packing nut so that the stuffing box drips no water at all can wear a groove in the prop shaft and ruin it. When the shaft is spinning, the stuffing box must allow a few drops of water per minute for lubrication. A variety of formulas exist to establish the number of times a stuffing box should drip while the shaft is spinning. Forget ’em. As long as the box isn’t dripping too much and isn’t running too hot, then all is well. Some boxes, particularly those used on sailboats, need not drip at all to meet this criterion as long as the packing remains moist. Take the box’s temperature after running at cruising speed for half an hour or so; it shouldn’t be more than 20 degrees F above the ambient water temperature. If you use an infrared pyrometer, you can carry out this test while under way. If you use a contact thermometer or your hand (too hot to touch is usually between 130 F and 150 F), shift into neutral, then check the temperature right away.

After repacking the stuffing box, use two wrenches to jam the locking nut against the adjustable packing nut. Never use a single wrench for this procedure because you’ll run the risk of spinning the nut off. More wraps, by the way, aren’t better where stuffing-box packing is concerned. Most boxes work very well with just three rings of packing; place the seams or joints at angles of 120 degrees to each other. Using too many wraps causes the shaft and box to overheat, which leads to packing failure as well as to galling of the shaft.

Finally, carefully inspect the stuffing-box hose and clamps at least once every sailing season. Use only all-stainless-steel, non-perforated hose clamps; avoid using T-bolt clamps because they’re prone to crevice corrosion in this application. Replace hoses at the first sign of fatigue, every five years, or whenever the shaft is removed, whichever comes first.

Steve D’Antonio, a regular CW contributor, offers services for vessel owners, boatbuilders, and others in the marine industry through Steve D’Antonio Marine Consulting. Next month, he writes about prop-shaft alignment.

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What You Should Know About Your Stuffing Box

The  stuffing box,  sometimes referred to as a  packing box  or a packing gland, has been around for many years; so many in fact, that some insist it was in use almost as far back as ancient mariners. We're not so sure about that, but regardless of the when, it is a well proven, reliable, and functional design. Most new boats since the year 2000 have shaft seals that require no packing, but sterndrive boats built before then have traditional stuffing boxes with packing.

The stuffing box is still an inexpensive method of sealing a rotating shaft when compared to the newer alternative system, especially in the larger sizes. A stuffing box does have some limitations, but so do many of the alternative shaft seals out there. One such limitation of the stuffing box is that it is not suitable for high-speed shafts.

This is not due to the stuffing box itself but rather the packing.  Stuffing box packing  has also seen its fair share of evolution and there are a few different choices out there, but they all have similar characteristics in common. The  stuffing box packing  is compressed to achieve the seal around the rotating shaft and the stationary housing. The sealing surface around the shaft is large and when the shaft turns, the surface friction creates undesirable heat.

This heat eventually deteriorates the surface of the shaft and reduces the effectiveness of the bearing packing. To mitigate the heat buildup, it is important to adjust the stuffing box correctly so that during operation some liquid passes by the seal to aid in lubricating the seal and reduce the heat buildup; and that when idle, no liquid passes by the seal. This can be done with constant attention, which is not always possible, and that leads to an annoying, constantly dripping shaft seal.

Aside from a lack of constant attention being a cause for stuffing box ineffective performance, other contributing factors are the condition of the shaft surface, the shaft alignment, and the condition of the bearings.  Interior shafting components such as the shaft coupling is also critical in ensuring that a shaft runs true. Shaft vibration, among other detriments, contributes to shaft sealing failure. Installing a flexible coupling reduces vibrations and can compensate for slight misalignment issues.

A stuffing box and the stuffing box packing will require maintenance, as the rubber hose will deteriorate over time and the propeller shaft seal will diminish as the packing wears out. Other hardware might need replacing as well, and thankfully there is still manufacturer support for even some of the oldest propeller shaft seals out there.

Alternatives to a shaft sealing with stuffing is a  dripless shaft seal.  There are a few types on the market with all achieving the same result--that being a dripless shaft seal. So, if a new stuffing box, shaft sealing, propeller shaft seal or other parts is on the maintenance list, take a look at what we have here for you at Go2marine.

Stuffing Box Maintenance

By Morgan Williams

The stuffing box is the seal around a boat’s propeller shaft that keeps the water out and allows the shaft to rotate freely. Ninety percent of all sailboats with auxiliary inboard engines have a flexible stuffing box with traditional packing gland that usually goes unattended until it begins to leak, usually at the worst possible time.

The traditional stuffing box consists of stern tube which is slightly larger than the prop shaft. A gland nut or packing nut threads onto the stern tube. Inside the gland nut is the packing, which creates the seal. The packing is wrapped around the shaft and inserted into the gland nut. As the gland nut is tightened onto the stern tube, the packing is compressed against the shaft, creating a seal. Lubricating the seal requires that when the shaft turns, two to three drops of water per minute drips out of the stuffing box. There is also a locking nut on the stuffing box that locks the gland nut into position.

There are three basic types of stuffing boxes. The rigid stuffing box is mostly used in powerboat applications. The flexible stuffing box is found in most sailboats, and the relatively new flexible shaft seals are used in both sail and powerboats. In a rigid stuffing box, the shaft comes through the stern tube where the stuffing box is bolted to the tube or hull and is affixed or part of the boat. In these applications, alignment of the shaft to the stern tube is critical for proper operation.

Check your boat’s stuffing box immediately after launching,and regularly throughout the season. Note the correct installation of the hose clamps on this flexible stuffing box.

In a flexible stuffing box, the stuffing box is connected to the stern tube with a short hose and four hose clamps – two on the stuffing box side and two on the stern tube side – that hold the assembly together. The hose is usually a four-ply steam hose, which is very strong and durable.

Shaft seals do the same thing as a flexible stuffing box, but without the packing seal. The seals have a bellows hose which is clamped to the stern tube. On the end of the bellows is a carbon/graphite flange. At the engine end of the shaft there is a stainless steel rotor which mates with the carbon/graphite flange. The stainless rotor is pressed against the flange, compressing the bellows and creating a seal between the flange and rotor. When the shaft turns, the carbon flange is fixed and the stainless rotor spins with the shaft. The graphite provides lubricant and a thin layer of water provides the seal for the shaft. Most shaft seals have a nipple for a vent hose to ensure that the stern tube remains full of water for cooling the carbon/graphite flange. On high-speed applications, the vent tube is connected to the raw water side of the engine, so seawater can be injected into the stern tube for cooling.

As with all jobs, disassembling a stuffing box is easier if you have the right tool, and the best tool for the job is the Ridgid E-110 wrench (you’ll need two).

There are three basic types of stuffing box packing: flax packing, Teflon packing, and graphite packing.

Flax packing has been around for 100 years. This greasebased packing can last for years and is very reliable. The one drawback to flax packing is that if the stuffing box gland nut is overtightened, flax packing can heat up in the gland nut, which causes dangerous temperatures and scoring of the shaft. So, when adjusting a stuffing box with flax packing, hand tighten the nut, adjusting it to reach the two to three drops per minute rule.

Teflon packing is great to use, and can last longer than flax packing. But this white material is hard to cut properly and requires a fresh razor blade. It’s also tricky to adjust the packing gland to get two to three drips a minute, and a number of adjustments may be needed to get it right.

Graphite packing is excellent because it’s a lubricant, which reduces the chance of burning the shaft. There are two drawbacks with graphite packing. It is very expensive and it can promote corrosion because graphite is high on the galvanic table, although I have been using it for years without an issue.

This “cutaway” photo, courtesy of the Chesapeake Bay Alberg 30 One-Design Association, shows the orientation of parts inside a flexible stuffing box. © alberg30.org

Repacking a stuffing box is a simple task. You’ll need two adjustable wrenches or two pipe wrenches. The tool that works the best is the Ridgid E-110 wrench. You must grab the gland nut and locking nut in opposing directions, to reduce the torque on the stuffing box hose. Once you have broken the lock nut and the gland nut free, spin the gland nut off the stuffing box towards the transmission. Now the fun really begins: removing the old packing. The best tool to use is the corkscrew-like tool available at any ship’s store. You screw the tool into the packing inside the gland nut and pull out the old packing.

To make properly sized rings of flax packing, wrap a length tightly around the prop shaft and cut across the rings with a sharp razor blade.

Now it’s time to size up the new packing. Packing comes in various sizes, with 3/16 inch and ¼ inch the most popular sizes for shafts in the one-inch range. It is very important to match the size of the packing to the opening in the gland nut. To cut the packing to length, wrap a length of packing around the shaft five times and pull it tight around the shaft. Using a sharp razor blade, cut across the rings with a diagonal cut. You now have four or five sized rings of packing. Now, insert the packing rings into the packing nut, offsetting the joints of packing from one wrap to another by 120 degrees. Generally, three to four rings will fit inside the nut.

Once the packing is in the gland nut, tighten the gland nut on to the stuffing box. I usually hand tighten the gland nut and then give it ¼ turn with a wrench, and then lock the nut to the gland nut. I make final adjustments after the boat is launched. As soon as your boat is launched, check the stuffing box. If it is leaking before you start the engine, it needs to be tightened up. Only tighten the nuts one quarter turn at a time. When the water stops dripping, start the engine and put the transmission into gear for a few minutes. Then shut down the engine and feel the stuffing box. If it is hot, the packing gland is too tight. Adjust the gland, restart the engine and recheck the stuffing box. Some warmth is okay in the beginning while the packing sets in. Remember to watch for the two to three drops a minute coming from the stuffing box while the shaft is turning.

Rings of flax packing should be inserted into the packing nut with the cuts offset by 120 degrees from one ring to the next.

While working on a stuffing box, it’s also a good time to inspect the hose clamps for corrosion and wear. Take a look at the hose for cracking or softness, indicating it’s time to replace it.

Happy motoring.

Morgan Williams operates Holmes Marine Services Inc., a full service mobile marine business specializing in sailboat repairs including diesel engines, electrical and charging systems, steering and propulsion. Morgan can be reached at 203-395-1051 or HolmesMarine@sbcglobal.net

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Replacing the hose between the propeller shaft stuffing box and shaft log tube

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Does anyone have any DIY experience with replacing the hose between the propeller shaft stuffing box and the shaft log tube? Boat is 34 years old and access is through the cockpit lockers. 1. Is this a DIY project? Any good resources? Will all bolts likely be frozen? Will I be able to do this with an ordinary socket set and wrenches? 2. How much would this likely cost at a yard in the Potomac River area of the Bay? The surveyor mentioned the possibility in the worse case that the shaft may have to be sawed off with a sawzall if I cannot unfreeze the bolts on the coupling.  

Stuffing Box Hose Replacement I am in the process of doing this now. I approached the job by reading whatever I could find on the web and a few books I have. Most articles suggested it would be a very difficult task due to age (1982 Peasrson 28-1). I also obtained an estimate of $1100. I used penetrating oil on the various parts and let them set for a week. I went to the yard yesterday and everything went perfect. The two set screws have been removed from the transmission coupling (trans in neutral - I don't know if this matters) and the prop shaft is 80% (about 1.5 ") out of the transmission. I added more penetrating oil and will return in about a week to pull it all the way out. The stuffing box hose has been removed and bronze device (coupler?) that holds the packing came apart quite easily. My advice would be to clear everything out of the area you are going to work in and lay in a couple of cushions to prop yourself on. Also, make sure you have good lighting and ventillation and have your phone in a spot you can reach if someone calls you. I do not have the project complete yet but I felt pretty good with what I accomplished and now know more about the boat than I did before whoich is always a plus.  

Traveling Light said: I am in the process of doing this now. I approached the job by reading whatever I could find on the web and a few books I have. Most articles suggested it would be a very difficult task due to age (1982 Peasrson 28-1). I also obtained an estimate of $1100. I used penetrating oil on the various parts and let them set for a week. I went to the yard yesterday and everything went perfect. The two set screws have been removed from the transmission coupling (trans in neutral - I don't know if this matters) and the prop shaft is 80% (about 1.5 ") out of the transmission. I added more penetrating oil and will return in about a week to pull it all the way out. The stuffing box hose has been removed and bronze device (coupler?) that holds the packing came apart quite easily. Click to expand...

Surveyor is right. The hardest part of the job is pulling the prop shaft (getting the prop shaft coupling off the shaft). You may be able to force the shaft out of the coupling by removing the bolts holding the prop shaft coupler to the output flange on the transmission output shaft, sliding the shaft away from the tranny, then putting a socket (or some similar-shaped object) against the end of the prop shaft, replacing the bolts, then tightening them, thereby forcing the prop shaft out of the coupling. You have to be careful not to bend either the prop shaft coupling or output coupling. As drastic as it sounds, it is sometimes easiest to cut the prop shaft. After the prop shaft coupling is removed, the rest is easy. Pull the shaft, replace the shaft log rubber tube, replace stuffing box, replace prop shaft, attach coupling, align prop shaft. This is a good time to replace cutlass bearing if it needs it, and to repack stuffing box.  

msmith10 said: As drastic as it sounds, it is sometimes easiest to cut the prop shaft. Click to expand...

msmith10 said: After the prop shaft coupling is removed, the rest is easy. Pull the shaft, replace the shaft log rubber tube, replace stuffing box, replace prop shaft, attach coupling, align prop shaft. This is a good time to replace cutlass bearing if it needs it, and to repack stuffing box. Click to expand...

You might want to price a replacement shaft and coupling to see how that stacks up against labor time and options for unsticking it. Bearing in mind that you are working in a confined space...sometimes a dedicated penetrant like Kroil or PBlaster will drop things apart. They attack the chemical bonds, they're not just lubricants like WD40. And when all else fails, a slurry of dry ice in alcohol, or a CO2 extinguisher, can be used to freeze-cycle parts and make them come apart without the risks of a torch. Used judicisouly, a torch has purposes too. But there are alternatives to just whapping it with a hammer, and sometimes penetrant and a properly improvised shaft puller is all it will need. Sometimes, it is easier to take a Sawzall and simply be done with it.  

Be sure to use a purpose made hose for this. Some think a conventional hose is appropriate for this use but it is not. The price is not enough to make a cheap alternative a good idea. replacing the cutlas bearing is also a good idea as is checking the shaft for true. After it is all back together and in the water for at least a week, check the alignment. HOSE FOR PACKING BOX 1 1/2"I.D. FOR 3/4" SHAFT 103999  

As has been said the coupler to shaft connection is the hardest part. If possible remove the coupler set screws and fill the holes with PB Blaster. Let sit for several hours, refill and tap the coupler/shaft z couple times with a hammer. Not hard, the vibrations help the PB do it's thing. If you have room, slide the shaft back and use a puller to get the coupler off the shaft. If no room use a socket, quarters, a large nut, what ever fits and try MS's method (it worked for me). Be very careful not to use too much force, the coupling flanges will bend. If it doesn't start to move, leave slight pressure on it and apply more PB and wait for a while.  

The worse case is having to cut the shaft and drop the rudder to change the shaft wheel steering and a quadrant you have to stand on your head to reach is bonus points for extra hard Its somewhat unlikely that IF you get the coupling off it will still spin true after X years of rusting in place when you put it back on  

tommays said: The worse case is having to cut the shaft and drop the rudder to change the shaft wheel steering and a quadrant you have to stand on your head to reach is bonus points for extra hard Its somewhat unlikely that IF you get the coupling off it will still spin true after X years of rusting in place when you put it back on Click to expand...

James, the shaft on a P28-1 is offset so it will clear the rudder once the prop is removed. And dropping the rudder on this boat is very easy if you have to. Also, if the boat has the A4, it will be a good time to repack the grease cup on the raw water pump and change the impeller.  

Had the same problem with a flexable coupling on a 1" dia shaft and getting the coupling off the shaft, tried hitting it, pullers, heating it, no chance. Then told an old trick, undo all the coupling bolts enough to put a 'large socket' (bigger i/d than the shaft) between the two coupling flange faces, re tighten all the coupling bolts, you then push the couplings apart no problem ! The flange on the end of the shaft usuallly has a key to locate it, so don't lose it in the bilge! Also check most flanges have a grub screw, pin or bolt locking it, so make sure you have undone them before starting. As Tim said the stern tube rubber seal is not ordinary rubber piping, it is special thicker walled especially for the job. Good luck it's fun!!!  

Tynesider said: Had the same problem with a flexable coupling on a 1" dia shaft and getting the coupling off the shaft, tried hitting it, pullers, heating it, no chance. Then told an old trick, undo all the coupling bolts enough to put a 'large socket' (bigger i/d than the shaft) between the two coupling flange faces, re tighten all the coupling bolts, you then push the couplings apart no problem ! ! Click to expand...

Started the repair... I decided to replace the packing box, cutlass bearing and propeller. Yesterday, I removed the propeller shaft bolts from the coupling, but could not release the shaft from the coupling. There is not enough room currently to replace the packing in the stuffing box, so I intend to replace not only the hose, but the entire packing box assembly. All parts are severly corroded. [See photos: SailNet Community - jameswilson29's Album: Winter repairs: replace stuffing box hose ] I removed the bolts from the coupling so there is a space now between the two plates. The transmission plate is a thick rubber pad. Should I replace this with a metal plate to gain more room for the stuffing box? I assume this reduces vibration. Does it also eliminate the need to align the coupling?  

jameswilson29 said: The transmission plate is a thick rubber pad. Should I replace this with a metal plate to gain more room for the stuffing box? I assume this reduces vibration. Does it also eliminate the need to align the coupling? Click to expand...

The "rubber" plate may be a shear plate, designed to shear if you get the shaft wrapped or jammed, instead of passing the shock on to the engine. Arguably a good idea. It wouldn't eliminate the need to align the coupling but might allow the alignment to be a little less critically done. The ones I've seen are more of a hard plastic or elastomer than plain rubber.  

I have done this job three times between my 2 Sabres. It's relatively easy and takes about 4-5 hours to do the complete job of replacing the shaft, coupling, and installing a new shaft seal. I've posted the procedure on Sailnet; see the following link for tips and PM me if you have questions. The coupler and shaft are a mated pair. They are machined together, so if you cut the coupling, do the job right and get a shaft made (and vice versa). http://www.sailnet.com/forums/gear-maintenance/42473-do-i-need-new-shaft.html Mainesail has awesome How-To tutorials. Applicable to this thread are: Replacing A Cutlass Bearing Photo Gallery by Compass Marine at pbase.com PSS Shaft Seal Installation Photo Gallery by Compass Marine at pbase.com [this is a priceless tip for separating the coupling from the shaft]  

Sabreman said: The coupler and shaft are a mated pair. They are machined together, so if you cut the coupling, do the job right and get a shaft made (and vice versa). ] Click to expand...

What is the shaft made of? You should try to determine what material your shaft is made of. We found that our 43 year old shaft was made of bronze and was badly worn at the Cutless bearing - so not worth the trouble trying to get it out in one piece. A Sawzall with a metal blade made light work of cutting the shaft for removal. Apparently, back in the day boat builders used bronze shafts in many boats as it was cheaper then stainless. Today, a stainless shaft will be cheaper and easier to find then one in bronze. I thought our drive train area was cramped but yours looks worse. You are not alone in tackling this job over the winter. What fun, eh?  

Attachments

Stainless steel 7/8" propeller shaft The propeller shaft appears to be stainless steel, 7/8" diameter. I would prefer to retain it, if possible, along with the coupling, instead of paying another $300 + $80 in parts. The propeller shaft seems to be in good shape so far.  

jameswilson29 said: The propeller shaft appears to be stainless steel, 7/8" diameter. I would prefer to retain it, if possible, along with the coupling, instead of paying another $300 + $80 in parts. The propeller shaft seems to be in good shape so far. Click to expand...

lol who started that thread "are sailors cheap" if the shafts not bent[warped] or pitted that idea of putting a socket[smaller than the coupling id between the couplings and gradually tighning the bolts /longer ones/ just might work while tapping/whaming/beating the hell out of it with a small/big/big ass hamer and maybe some torch heat,or cutting off the old coupling,put on a new one then check the runout with a indicator on the mating face while turning the shaft  

OK. So your shaft is stainless and may not be 34 years old and you'd like to save it. You are going to have to try to press the shaft out of the coupling then. I'd suggest getting a steering wheel puller kit from an auto parts store (see pic below). Having the 'puller' tool can save you from having to compress something between your output flange and shaft flange, if you can make enough space to insert it once the couplers are apart. This will be a much bigger PITA to do in the boat. The problem with the 'press out' method is that you can ruin both the output coupler and shaft coupler in the process. Another fun part of this job (if you're going whole hog) is removing the old Cutless bearing. We tried pressing it out with a threaded rod and fittings but no go. Sawzall to the rescue again (2nd pic).  

What MaineSail posted/said! There are a bunch of parts you can set out of true in the drive train using the press method for separating the pieces. I priced a new SS shaft for my boat (just over 3') at around $200. New coupling (recommended) and a new output flange plus any possible transmission damage would cost quite a bit more to fix then a new shaft. I'm seriously considering getting a new coupling with a new shaft. Hey MaineSail, Do you have any comment on using a shaft coupling with a split hub? Like the one pictured over at Moyer's website? (Sorry, you have to scroll down to "Direct drive prop shaft coupling, with split hub (1 inch)" Moyer Marine Atomic 4 Engine Rebuilding and Parts ) I also have a lightly used 'drive saver' I was thinking of using with the new shaft and coupling. Something like this: 504 Drivesaver™ Drivetrain Protection Any comment on using these components in my rebuild? My set up is a direct drive transmission from an Atomic 4 engine in an ancient Tartan 27 if that matters. This is all fairly new territory for me so I am looking for the voice of experience. Thanks.  

As usual, mainsail is the voice of reason and correct procedure. On our current boat, I replaced everything aft of the transmission. I only needed to replace the cutlass bearing but the shaft was original bronze and scored, and the stuffing box leaked. I had just bought a $75,000 boat; saving a couple hundred $ seemed pointless. So I replaced everything (shaft, coupling, shaft seal, cutlass bearing) and am reaping the benefits 6 years later. This is not a job where it's even remotely advisable to attempt to save a few dollars.  

Thanks for all the responses. O.K. - I won't be cheap about it - I ordered the Buck Algonquin split shorty coupler and shaft removal tool. I hope the propeller shaft is in good shape. How and where would I find a competent shop to fit and face the coupler to the propeller shaft? The boat is in a small marina on the Northern Neck of Virginia and I live near Richmond, Va., which has a small industrial base. Is this something an ordinary machine shop can do, or does it have to be a "marine" machine shop?  

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i would think any machine shop that has a lathe and knows how to use a indicator even a automotive btw if you press the coupling onto the shaft first you will need to move the engine and slide the shaft from the inside  

Maine, all this sticking the shaft in the coupling, lathing everything, not just "bolting it up"...is this akin to "blueprinting" an engine instead of just building it? Is this really necessary every time a shaft is popped off? Or is it more for the folks who simply prefer ironed shirts to permanent press?  

That is why a split coupling makes sense - the engine doesn't have to be moved.  

So after the split coupling is fitted and faced to the shaft, it can be split and re-attached without more fitting and facing?  

Yes so long as it is new you're fine. If it gets a few years old and rusty, and you remove it, you'd be best to drop it at a machine or prop shop to have it re-checked. Most will check the fit and face for just a few bucks.  

i would think so,just use a .002 feeler gage between the couplings while you realign the engine  

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Black Box Techniques

Black Box Electronic Fishing Technology

The most comprehensive book on Black Box technology ever assembled.

Learn how and why fish are attracted to a downrigger cable that gives off a small electric charge.

Includes step by step procedure you can use to determine if your boat attracts or repels fish.

Learn the principles of the Black Box and how to optimize your boat's charge for each species of fish.

This may be purchased at tackle dealers or at www.protrollsales.com

You may read this book online for free below:

Introduction

This book is about the use of a small electrical charge on a downrigger cable or transom mount to catch more fish.  The principles are well established, particularly with certain species of fish.  If you fish for electrically sensitive fish, and you follow the principles in this book, there is no question that you will catch more fish.  However, to be successful, you must carefully complete a three-step process.

1.  Study this book carefully and you will learn enough about electricity and downrigger voltage to check your boat and make any necessary adjustments.

2.  Rigorously check your boat for proper bonding, electrical leakage and zinc anode conditions.  Problems here are the reasons a lot of boats fish poorly.   A Black Box will help even the wost of boats but it cannot overcome serious electrical problems.

3.  If you install a Black Box, be sure it is set up properly and you understand the readings.  As you use it, continue to monitor the base reading on the boat to ensure everything continues to work correctly.

Chapter I. Catching Fish with Electricity - The Concept

Ever wondered why some boats consistently out fish all the others? Every experienced fisherman has seen it. Two boats using the same lures, same gear, same depth and one will catch most of the fish. The answer may not be as mysterious as it seems. Research in recent years has shown that positive voltage around your boat hull or  downrigger cable can have a major influence on fishing results. As a boat sits in the water, very small electrical currents are generated as the minerals in the water react withthe different

metals on the boat. If the boat is outfitted correctly, a very slight positive

electrical charge will surround the hull. Fish are attracted to this positive

charge. If the boat is set up wrong, an incorrect charge surrounds the hull and

fish will be repelled. Fishermen who learn how to take advantage of this will

significantly improve their catch.

Nearly one hundred years ago, Russian scientists studying fish behavior

learned that most fish have reactions to weak positive and negative electrical

charges in the water. Some fish, like sharks, will react strongly to the tiniest

of electrical fields. Fish are attracted to a positive charge and are repelled by a

negative charge. Different species will show varying degrees of electrical reaction. Some of the fish showing the most sensitivity include salmon, kokanee and trout. Natural electrolysis causes electricity to flow from the metal hull parts of your boat to your downrigger cable. If the boat and downrigger are set up right, this will place a positive charge on the downrigger wire which attracts fish. A black box will stabilize this charge at the ideal voltage.

Modern downriggers offer fishermen a big advantage in getting the correct positive electrical charge around their boats. If the downrigger is insulated, natural electrolysis between the stainless steel downrigger cable and the metals of the boat will create a positive charge. The fisherman can then control and stabilize this charge to the ideal voltage by using the Black Box.

Commercial salmon trollers have used the Black Box technique to increase their profits many thousands of dollars each year by imposing a voltage on their stainless steel cables. By using multiple cables all connected to the Black Box, they can create a complete zone of positive electricity around the boat hull. Downrigger fishermen can create this same field with the Black Box.

The Black Box will significantly improve results when trolling. When used with the nondownrigger transom mount, it can also significantly improve results in rivers and shallow bass areas.  With or without downriggers, it is also effective in  mooching, jigging and still fishing applications. In these instances, some fisherman will use stationary downriggers and others will rely on the transom mount.

Every boat takes on a natural electric charge in the water because of the different metals in contact with the minerals in the water. The zincs on the motor will be positive in charge. This drives the bonded metal parts on the boat to a negative charge. Any unconnected metals like downrigger cable will take on a positive charge.

A voltmeter with a scale of zero to one volt will measure the natural voltage of your wire. Here the natural voltage reading is .782 volts. Note the positive lead is touching the downrigger wire. The negative lead is connected to the engine.

All metal parts in contact with the water should be connected together by a heavy bonding wire

Chapter III. How to Test Your Boat's Electrical Charge

The effects of underwater electrolysis and the corrosion damage it can cause to metallic boat parts have concerned boaters for many years. Only in more recent years has it been learned that these same factors can have a significant role in how a boat fishes. This chapter describes a step-by-step procedure that you can follow to see if your boat is adequately protected from galvanic corrosion (electrolysis) and is set up to maximize the positive effects of a positive voltage on fish.

Even if you may never intend to purchase a Black Box, you should carefully follow these steps. You can save yourself a lot of grief from corroded boat parts and may considerably enhance your fishing results.

Whenever a boat is in water, the different underwater metal parts interact with each other to form a weak battery. Electrical currents flow from one metal part to another depending on the type and placement of the metals involved as well as the mineral content of the water. Typical metals used on boats include aluminum, copper, steel, brass, stainless steel and zinc as sacrificial anodes. If a boat is set up properly all the corrosion is channeled so it dissipates harmlessly in the zinc sacrificial anodes. As it does so, it creates a positive field around the vessel which can be helpful in attracting fish. There are three seperate electical sections:

1. The zinc anodes are located on the outboard motor, outdrive or propeller shaft.  Because of the low nobility of zinc, these will be charged positive.

2. The hull itself and all the metal  parts in contact with the water will have a negative charge.  These parts include the hull if it is metal, motor shafts, outdrives, electric trolling motors and thru hull fittings.  All these metal parts must be interconnected with a bonding wire.

3.  Other metal objects in contact with the water like stainless downrigger cable or wire fishing line that are not connected to the boat will be charged positive.  By using a voltmeter with a scale from zero to one volt, a series of measurements can be taken which indicate whether or not the boat is being protected from harmful electrical corrosion and if the downrigger cable has the proper positive field to attract fish.  Following is the step-by-step procedure.

1.  Inspect the inside of the hull.  If the boat is fiberglass or wood, there should be a copper bonding    wire running along the bottom of the hull connecting all the underwater metal fittings together.  For example, it should run from the engine or outdrive to the metal fuel tanks, metal water tanks, through hulls, trim tabs and motor shaft and stuffing box.  Be sure the bonding wire is not broken and that the connection to each fitting is clean and tight.  The connections are easy to check with a volt/ohm meter.  With the boat in the water, touch the positive lead from the volt meter to each fitting and the negative lead to the bonding wire.  If the meter shows a reading of .010 volts or higher, clean the connection and recheck.  If it is below .010 check the same connection with an ohm meter to ensure continuity of less than one ohm.  If the boat is out of the water on a trailer, you can use the ohm part of this test by itself.

If the outboard is an electric start, it is automatically grounded and nothing further needs to be done.  If it is not an electric start, it can be bonded by running a wire from the metal on the motor to a ground point on the boat hull.  If you are not sure the motor is grounded, you can use a volt/ohm meter to check.  To test for bonding, connect the negative meter lead to the negative terminal of the battery and test for continuity to the boat hull or bonding strap as well as the outboard motor.  If there is no continuity, install a bonding wire (10#) from the negative terminal to the hull and to the outboard.  One of the most common problems is the failure to bond a kicker motor to the hull.  Many are not electric start and must be bonded to avoid problems.

2.  With the boat in the water, lower a downrigger cable into the water a few feet. It is best to do this away from marinas or docks where a number of boats are moored. Stray electrical currents from battery chargers or electrical systems can distort your readings. It is also best to have a vinyl-covered downrigger weight and an insulated end snap connecting your weight to the cable.

3.  Turn off everything electrical on the boat. Turn off the master connect battery switches if you have them. Then connect the negative lead from your volt meter to the negative battery terminal, the engine or to one of the bonded metal fittings on the hull.  Connect the positive lead to your downrigger cable near the spool or along the arm. In saltwater or most bodies of freshwater, you should get a natural voltage reading of between .7 volts and .8 volts. If the reading is significantly outside this range, you have a problem (see later problem section).  The voltage may vary slightly with different water conditions.

4.  One by one, turn on the boat's different electrical systems and watch the voltmeter. Start first with the battery switches. Next, turn on the bilge pump. Start the engine and then each of

the other electrical devices. If your natural voltage reading changes by more than .05

volts from its starting point with any of these steps, you have an electrical leakage

problem or a problem in the negative battery circuit. These are quite common in

accessories like bilge pump connections where a slight amount of positive electricity

can leak into the water in the bilge.  If you have electric downriggers, be sure to turn

them on as part of your checkout.  To test them,you will have to lower them deeper

and then hold your positive lead against the moving downrigger cable as it rewinds.

Leakage of electricity from the plus side of a boat's power system creates "hot spots" and will ruin a boat's fishing ability. Here an isolated screw on a battery switch shows a leakage reading of .59 volts. This charge will pass along the fiberglass, through the bilge and directly into the water around the boat. This switch needs to be removed and all surfaces cleaned free of the dirt and crust that are allowing the electricity to pass.

Chapter IV. Black Box Operation and Recommended Voltages

1.  Plug in the power to the Black Box. Be sure the Black Box switch is turned to the "off" position (all the way counter clockwise).

2.  Be sure the metal contact sleeve is in place on the downrigger wire and connected to the Black Box.

3.  Drop the downrigger to fishing depth or at least a few feet under the surface.

4.  Turn the knob to the "on" position. Put the mode lever in the Natural Voltage position. If you get a normal voltage reading (.7 to .8), you will know all wires and connections are functioning correctly. If for example, you get a zero reading, you will know something is wrong. To apply a selected voltage to the downrigger wire, flip the switch to the Applied Voltage position. You can then turn the dial to set any reading you want from zero to one volt.

Recommended Voltages

There has been a great deal of work done on the correct downrigger wire voltages for salmon, trout, kokanee, bass, laketrout and other species. The following table should be used as a suggested starting point. You may find other voltages that work better.

Species Voltage

Sockeye Salmon .750 volts

Kokanee Salmon .650 volts

Halibut .450 volts *

Laketrout (Mackinaw) .650 volts

Rainbow & Brown Trout .650 volts

Cutthroat Trout .650 volts

Black Bass .750 volts *

Sharks .400 volts *

Striped Bass .650 volts *

Sturgeon .500 volts *

Catfish .500 volts *

* Further research may change this recommendation.

The Black Box is very effective in improving results when trolling. It should be connected to all the downriggers on the boat so it provides a uniform positive charge completely around the hull. There is a zone of fish attraction created at the downrigger wires. The fish will come to the wire. Often, results will be best by using a very short drop back leader between the downrigger release and the lure or bait.

These photos show the Black Box in a typical "Natural" voltage position and an "Imposed" position. In the left photo the lever is in the "up" position and the Box shows a natural reading of .768 volts. In the right photo the lever has been moved to the "down" position and the dial has been adjusted to an imposed setting of .608 volts. In most instances you will be lowering the natural voltage to get the reading you want. From time to time while you are fishing, it is a good practice to switch the mode switch to the natural reading position. If you get a normal natural reading, this tells you that all your connections are working. If you are running multiple downriggers on one Black Box, you should make this test on each downrigger with one in the water at a time. If you get a zero natural reading, the first thing to check is the contact sleeve riding on the downrigger cable. Sometimes scum will insulate the contact. You can usually get it working by wiggling or sliding it back and forth on the cable.

When you are trolling with the Black Box, the electric  attraction zone is set up between the positively charged  downrigger cable and the negatively charged outdrive  and other metal boat parts in contact with the water.

Chapter V. Tips on Adjusting the Black Box

If you are not catching fish, the natural inclination is to turn the Black Box up to a higher voltage. Often this is the wrong way. Most of the time you want to reduce the natural electrolysis voltage for best results. Sometimes you can tell if you have the Black Box voltage too high by watching hooked fish as you reel them near the boat. If your voltage is too high, they will fight violently and will try to swim under the boat and into the prop wash where the voltage is lower.

Larger fish need less voltage than smaller fish. Their large body size makes them more sensitive to the electric charge. For very large fish (over 20 or 30 pounds) you may want to turn the voltage down about .1 volt. You should also lower the voltage for extra sensitive fish like sharks. Note: As you dial the Black Box, it will show readings down to zero.

As you are searching for the best voltage, make very small adjustments. Often, a small change is all that is needed to attract the fish you are after.

If you are running more than one downrigger, it is best to hook all of them to the Black Box to avoid having different voltages on each downrigger. By connecting all of the downriggers together, it creates a uniform positive charge around the entire hull which is highly desirable. The Black Box has the power to run up to six downriggers.

A number of questions arise on how to adjust the Black Box as you fish deeper. There is less loss than you might suspect as you go 50, 100 or even 200 feet down. Each section of downrigger wire is reacting separately with the boat's hull and its zinc, thereby creating its own natural voltage through the process of electrolysis. Using insulated wire, we have measured this voltage as deep as 400 feet and found very little change in the charge generated. The Black Box is adjusting and controlling your rate of natural electrolysis to the setting you desire. This will carry right down the wire in both fresh and saltwater.

Zinc annodes are installed on outdrives or motor shafts to protect from electrolytic corrosion. Note the heavily corroded condition of this zinc. When the zinc is more than 50% corroded, it should be replaced.

Chapter VI. Using the Black Box Without Downriggers

Many fishermen would like to have the advantage of a Black Box but they do not use downriggers. River fishing for salmon or shallow water fishing for bass are two examples. Shallow water jigging is another example. Pro-Troll developed a transom mounted wire system that works just as well in attracting fish as downriggers. A piece of downrigger cable is stretched across the transom of a boat and connected to the Black Box. The field around the boat can then be adjusted to the optimum voltage.

In shallow water, the electrical field around a boat will either attract or repel fish below the boat. If the boat is "hot" fish will be repelled. A Pro-Troll transom mount kit allows a Black Box to correct the charge so that fish are attracted.

The transom mount system is composed of a piece of stainless steel downrigger cable stretched between two insulators on the transom of your boat. It is positioned so it is underwater. An insulated wire runs from the cable up into the boat and connects to the Black Box. The Pro-Troll transom mounting kit contains the parts needed for this installation. (1) A piece of downrigger cable, (2) three insulator pad mounts to hold the cable away from the boat, (3) a piece of insulated tubing and (4) the necessary hardware to go to the Black Box. The three insulators can be fixed to the transom with the self sticking adhesive included or they can be mounted with screws.  The Pro-Troll Transom Mount Kit #1505 can be purchased from Pro-Troll retailers.  In many cases fishermen are able to find local materials and construct their own transom mount. 

Before installing the transom kit, thoroughly clean the locations for the insulated mounting pads.  Clean off all grease, dirt and foreign materials.  The pads can be secured to the boat using the adhesive tape on the back of the pads.  For maximum bonding it is recommended that the six stainless steel screws also be used to attach the pads. It is not necessary that the #1 and #2 pads be mounted in the center of the transom as shown in the drawing. They can also be mounted to one side. (1) mount the three pads as shown. (2) Feed the stainless steel wire through the small hole in the #1 pad and then through the #2 pad. At this point slide one of of the small wire sleeves down next to the #2 pad. Pull the wire tauut (if using only the tape mounting don’t over pull as you might break the tape bond on the #1 pad). Crimp the sleeve with a pair of pliers or crimping tool. This will secure the wire in place. Run the wire through the #3 pad and then through the last sleeve. Crimp the sleeve to prevent the wire from coming out. Cut a piece of insulation (supplied) the length of the remaining wire less one inch and feed it over the wire. Place the connector on the end of the wire and securely crimp it in place. Plug the connector on a white wire coming from the Black Box distribution post into this connector. Make sure the bare part of the stainless steel cable does not touch any metal parts on the boat.

The Black Box can also be used effectively with bottom feeding fish like sturgeon and catfish. In this instance, it is best to use a rod and reel with insulated wire line. Peel off the insulation to leave a short bare section near your bait. You will also have to leave a bare piece of wire somewhere in your reel. You can then clip an alligator clip from the Black Box to your wire line. Both catfish and sturgeon use electro sensor cells to find prey. The transom mount will also help catch these fish by neutralizing the boat.

Chapter VII. Electrical Sensitivity of Fish

Research into the behavior of fish in the presence of electricity started over one hundred years ago. Scientists and biologists have long been fascinated by the ability of some fish to use electricity and magnetism to navigate and find prey. Even though a lot has been learned, in many ways the field is still in its infancy. It is known that all fish have some reaction to electric stimulus in the water; but exactly how fishermen should take advantage of this, remains a mystery with most species. Lets start with a summary of what is known.

Fish use electricity in varying ways.

As early as 1917 scientific studys had revealed that a number of animals including fish, demonstrated responses to the presence of tiny electric fields in their environment. Some of the earliest work was done on catfish which turned out to be very electrically sensitive. Scientists, PARKER and VAN HEUSEN, tested blindfolded catfish in an aquarium. When glass or inert rods were inserted into the tank, there were no reactions. However, when metal rods were inserted, there were immediate reactions. With some metals, the catfish would swim to the rods and with other metals they would swim away. The reactions came from galvanic reactions between the metals and the water. Later the same scientists created the same reactions with induced electricity instead of the rods.

By the 1950's hundreds of fish were classified and ranked by their degree of response to an anode (electrical) reaction. It was learned that many fish have the capability to sense the electrical impulses given off by other fish and some can even sense the tiny voltage gradients created by ocean currents and river water movements in the presence of the earth's magnetic field. All fish have a reaction to an electrical field but it differs. Some fish are attracted to the field, some are frightened by it and attempt to hide and a third group appears to be immobilized by it. Interestingly, however, all of these groups react towards the positive charge and away from the negative. Even fish that are frightened and attempt to hide, will move in the direction of the positive anode.

In 1982 a study by Mr. L. A. Balayev of the Moscow All-Union Research Institute for Sea Fisheries concluded in part:

Fish are divided into three groups: those with an anode reaction, those without and those in the intermediate group.

Irrespective of the presence or absence of anode reaction, all species of fish distinguish the anode (+) from the cathode (-) and prefer the anode.

The anode reaction occurs in two stages: (1) distinction by the fish of the polarity of the current, (2) movement towards the anode or absence of movement depending on the ecological stereotype of behavior of the fish.

The presence of an anode reaction is characteristic of active and agile species. Fish that are not very active respond to the action of the (electric) current by hiding.

Some fish are unique in that they have special cells on their body surface that are electro receptors. These nerve cells have the specific capability of reading electric signals. Sharks, rays, sturgeon and catfish are some of the better known species of this type. Not only are they attracted by an anode reaction but they will use their electro receptors to find prey hidden or buried in the mud or sand. They can sense the electrical nerve discharges of their target.

Following are some of the scientific conclusions relating to game fish.

In the rankings of electro sensor capabilities of all fish, sharks and rays are at the absolute top of the list. Dr. Theodore Bullock of the Scribbs Institute of Oceanography, is one of the foremost world experts on Electro reception. His book Electroreception was published in 1986. Bullock ranks sharks as probably 1000 times more sensitive than any other fish. He indicates that sharks and rays have the documented capability to navigate solely using the earth's magnetic field as their guide. In the June 1991 issue of National Geographic, researcher Adrian Kalmijn noted that a "shark recognizes an electric field in the order of five-billionth of a volt per centimeter."  Kalmijn offers this perspective. "Plant electrodes 2000 miles apart on the ocean floor and power them with a 1.5 volt flashlight battery. That is a very weak electric field. But every shark in between those electrodes will know what you are up to."

An interesting series of tests on sharks were run by a scientist named KALMIJN in 1971. He successfully demonstrated that sharks and rays use electro sensors to find prey buried in sand. He buried live flatfish. When sharks were stimulated to feed, they would go to the exact spot in the sand and dig out the flatfish. Kalmijn then substituted a charged wire electrode for the flatfish. The sharks would tenaciously dig to the electrode and return time and time again even though they found no prey.

Salmon do not have electro sensor cells like sharks but they have been found to be one of the species strongly attracted to an anode reaction. Research at the University of British Columbia demonstrated that salmon can distinguish the earth's magnetic field. When baby salmon in test tanks were subject to magnetic fields imposed outside the tanks, the majority of the fish would orient themselves to one side of the tank. It is believed salmon use this sense in their migration patterns. Many years ago the U.S. Fish and Wildlife Service learned that they have to be very careful with galvanic reactions (electrolysis) around salmon hatcheries.

In many instances salmon must swim through culverts or other metal structures in their upstream migration. If the dissimilar metals are used such that a negative galvanic reaction is present, the salmon will refuse to enter the culvert or structure. The Fish and Wildlife service carefully neutralizes these structures to ensure salmon passage.

In 1979 Daniel Kenichi Nomura completed his masters thesis at the University of B.C. by running controlled voltage tests aboard boats of commercial salmon trollers. For King salmon, Normura demonstrated that troll success "was higher for the positive 0.5 volts condition and not significantly different for the positive 1.0 volts condition, with respect to the paired control conditions of zero volts." The same tests for sockeye salmon showed the best attraction voltage for this fish was 1.0 volts. Nomura also attempted to prove or disprove the theory that optimum voltage has a bearing on the size of salmon caught but his results were inconclusive.

Catfish also possess electro receptor cells. Like sturgeon and sharks they use this capability to find prey in the muddy murky waters they habitate. Many cat fishermen know the old trick of throwing flashlight batteries into the water to catch catfish. The electrical charge attracts them.

Sturgeon are another species that possess special electro receptor cells. There is a row of these cells along the sturgeons snout. They use this capability to detect tiny electrical discharges from clams, mussels and other invertebrates buried in the mud or sand. Fishermen who can duplicate these nerve discharges in their bait using the Black Box technology have a fishing advantage.

Kokanee are one of the most sensitive salmon to electric voltage. Kokanee are the landlocked cousins of the sockeye salmon. With a voltage of usually .600 volts, kokanee will congregate around a downrigger wire and will follow along as you troll. Most kokanee experts rely on the Black Box to improve their catch.

Studies on trout have linked their response to electrical fields to metabolism. Active fish like trout have a higher rate of metabolism and demonstrate more electrical sensitivity. Research has shown that the best Black Box setting for most trout is .65 volts.

Laketrout have also demonstrated the capability of sensing weak electrical fields in the water.  The Black Box has provenvery effective in attracting them.  A setting of .600 to .650 is recommended.

Salmon, trout and many other fish have what is called a lateral line down their sides. In this line there are hairlike nerve cells that can detect vibrations and weak electric fields. The same kind of cells appear on the head of the fish.

Chapter VIII. The Chemistry of The Electric Charge on Your Boat

Electrolysis or galvanic action as it is sometimes called is the generation of electricity through a chemical reaction. Any time dissimilar metals are present in an electrolytic solution a battery will be created and electricity will flow. The amount of electricity generated depends on the metals involved and the nature of the electrolytic solution. Sulfuric acid is a strong electrolytic solution. It is used in your car battery to generate enough electricity to start the car and power your electric systems. Water containing minerals is a weak electrolytic solution but it will still generate electricity.

There is a table ranking all metals by what is called nobility. When a metal of high nobility is coupled with a metal of low nobility, more electricity will be generated. Zinc is very low in nobility and will react strongly with almost all other metals. This is why zinc anodes are placed on boats. Downrigger wire, which is stainless steel, is relatively high on the metal nobility table. The reaction between stainless steel wire and zinc will normally generate about .8 volts of electricity in saltwater.

If any two of these metals are connected in an electrolyte, the one standing higher on the table will be anodic, lower one cathodic. The further apart they are in the series, the greater will be the galvanic (electrical) potential between them. For example, if the stainless steel reading of .24 (downrigger wire) is subtracted from the zinc reading of 1.04 (boat anode) the result shows a voltage potential of .80 volts being generated. This is what we would expect to read if we tested the boat's natural voltage.

Most outboard motors have a small zinc anode fastened to the motor shaft. It is very important that this be present and that the motor be bonded to the hull or other metals on the boat.

Chapter IX. Black Box Installation

This schematic shows the layout of the Black Box installation. Run the wires in out-of-the way places on the boat and connect them as shown.

Run positive and negative power leads from an electrical source that is connected to the boat battery to the location where you will mount your Black Box. Connect these leads to the female quick disconnect socket. Be sure to connect the positive lead to the terminal matching the red wire on the plug on the Black Box. If this line is not fused, it is recommended that you do so to protect against shorts. A three amp fuse will be adequate. Do not run the Black Box from positive or negative terminals that are heavily loaded with other equipment like radios, fish finders etc. Overloaded circuits can cause distortions in the voltage the Black Box places on your downrigger. If you have heavily loaded circuits, you need to run a new positive and negative lead from your boat battery to the Black Box.

If you are going to run multiple downriggers on the Black Box, you should locate the distribution post near the stern of the boat. Thread the white wire coming out of the quick disconnect plug to the distribution post. Try to locate this wire where it is protected and you won't trip over it. Most boats have wire bundles running down the side gunnels.

Run a connecting wire from the distribution post to the vicinity of each downrigger location.

Thread the contact sleeve onto your downrigger cable and connect it to the white plug in wire. Secure the contact sleeve wire lead to the downrigger boom with the two cable ties included with the kit. Place the contact sleeve far enough out on the boom to avoid interfering with the downrigger operation, usually about 12 inches. You should attach the cable ties approximately 1 inch apart and positioned on the boom so that the contact sleeve does not interfere with the normal lead-in of the cable into the downrigger spool. The heads of the cable ties should be on the opposite side of the boom from the white wire so that they can be pulled tight. Plug the wire on the downrigger wire into the lead coming from the distribution post.

Note: The Black Box should be mounted where it can be unplugged and removed when not in use. It is moisture resistant, but not water proof. It should be removed and stored in a dry area.

The Black Box can be mounted on any vertical or horizontal surface. It should be mounted in a dry location. It is water resistant but not water proof.

The contact sleeve should be mounted so it rides the wire but does not pull the wire out of its normal track.

Using the Black Box with the internal 9 volt battery

Open the compartment on the back of the Black Box and install a 9-volt battery. With a quality battery the Black Box will normally operate for up to 70 hours. If 12 volt power is available, it is best to run the Black Box from boat power rather than the 9 volt battery. If the 9 volt battery is weak, your voltage readings can be distorted.

The Black Box can have the 9 volt battery installed and be connected to the boat battery at the same time. If you have the 9-volt battery installed, you can use the Black Box to check your natural downrigger readings and your connections. See Chapter 3 on testing your boat.

To use the Black Box with only the internal 9 volt battery, you must have the negative wire (black) coming from the Black Box connected to your motor or another grounded part on the boat.

Chapter X. Troubleshooting

Problem: When the Black Box is first turned on, there is no natural voltage reading.

a. The unit may not be turned on. Turn the knob clockwise until the unit is turned on. Be sure the mode switch is in the "up" natural voltage position.

b. The downrigger contact sleeve is not plugged in or is not making proper contact with the stainless steel wire.

c. The downrigger wire is not in the water.

d. The zincs on the boat are worn out or are not functioning therefore resulting in a low reading below the minimum of .5 volts.

e. If you are in extremely pure freshwater, there may not be enough dissolved minerals present to create a normal voltage. Most bodies of freshwater will show readings very close to salt water but you may have found an exception.

Problem: Your natural voltage reading is too low (.1 to .5 volts)

a. Your boat zincs are worn out or may be covered with scum or white oxide powder. If so, the zincs will not work properly. They should be cleaned or replaced.

b. The boat does not have enough zinc to protect the vessel. If you have cleaned the zincs and still get a low reading, more zincs may be needed.

c. The sacrificial anode on the outdrive or outboard is an alloy of aluminum and not zinc. Some manufacturers have replaced zinc anodes with alloys of aluminum. Because of the higher nobility of aluminum, you will get a lower natural voltage reading. Your natural reading could drop by as much as .2 to .3 volts.

d. The boat is not properly bonded. Check the bonding connections and be sure all metal parts touching the water are bonded together with a wire connected to the battery ground. A kicker motor that is not bonded to the ground system of the boat will cause this problem.

e. Your downrigger wire may be corroded or partially insulated. Older downrigger wire often can become coated with scum or corrosion. This has the effect of partially insulating the wire and will cause a low natural voltage reading. You can usually scrape off a short section of the wire and retest to see if this brings the voltage up. Some downrigger manufacturers paint or coat their wire to remove the shine. This can have the same effect. The wire is partially insulated and will show a low reading. The Black Box will correct both of these problems and bring the voltage to the correct level.

Problem: Your natural voltage reading is near zero or negative.

a. You have the voltmeter connected backwards.

b. The downrigger wire or spool is grounded to the boat. Find the source of grounding and insulate the downrigger from the hull.

c. There is insufficient or pacified zinc on the boat. The zinc should be cleaned or new zinc should be installed. (Clean zincs with a stainless steel wire or bristle brush. Do not use a common mild steel wire brush).

d. The hull is not bonded. An aluminum boat that does not have the hull bonded to the engine can cause a negative downrigger wire reading. Run a bonding wire from the motor to the battery ground post and be sure the hull is also connected to the negative battery terminal. If you use two batteries in the boat, the ground terminals of both must be connected together and grounded to the boat hull.

Problem: Your natural voltage reading is too high (more than .800 volts)

a. There is electrical leakage in the hull. A positive connection is leaking some electricity across your hull and into the water. This is quite common particularly with battery switches or bilge wire connections. Try to find the source of the leak by using the Quick Boat Check Procedure in Chapter III. You can disconnect one circuit at a time (removing the fuse is a good way) and watch for a change in the natural voltage reading. This problem is called a "hot boat". It is a very common and the boat will have a very hard time catching fish. You can test the whole boat at once by disconnecting the positive terminal from the battery. If your reading on the downrigger cable changes, you have leakage somewhere.

b. Your downrigger spool and wire are not insulated from the boat's electrical system. Some downrigger manufacturers impose a strong positive charge on the downrigger wires as a means of controlling weight retrieval (short stop system).

c. Your downrigger wire has been changed to a metal with higher nobility than stainless steel. Monel wire will show higher readings than stainless.

d. The water where you are doing your testing is high in acid content. Heavy concentrations of certain algae in freshwater can cause overly high natural readings on your Black Box. If you are testing in a heavy algae concentration, this may be the only problem. Before you assume something is wrong, test in clearer water.

Problem: When you test the voltage on your downrigger cable with a seperate voltmeter, the voltage shows lower than the reading on the Black Box.

a. This is generally caused by the ground wire that comes from the Black Box to the negative side of the battery being overloaded. If there are several pieces of equipment like radios, fish finders and lights all hooked to a common ground wire, it can become overloaded and have a voltage drop. If the Black Box is hooked to this same wire, it will read a false ground level and send out an incorrect differential voltage.

b. Turn off all the auxiliary equipment on the boat and take new voltage readings. If this corrects the voltage error, the Black Box should be set up with a separate ground wire back to the battery.

c. Check the connections on the ground wire to be sure they are clean and making good contact. A corroded connection can cause the same problem as an overloaded wire.

d. The voltmeter in the Black Box is extremely accurate. This is not the problem.

Chapter II. Factors that Affect Your Boat's Electrical Condition

To take advantage of an electrical charge to catch fish, there are several criteria which must be observed. Even   without a Black Box there is "natural" voltage generated on a downrigger cable that can significantly assist the downrigger owner in improving his catch. With or without a Black Box, the following steps should be observed.

1.  The downrigger spool and stainless steel cable must be insulated from the boat hull. This allows a natural voltage to be generated on the cable. Most downriggers with plastic spools are insulated by the manufacturer. Some manufacturers intentionally connect the downrigger cable to the boat's electrical system as a means of stopping the retrieve when the downrigger weight breaks the water surface. This does the opposite of what you want. A high voltage is placed on the downrigger cable which repels fish.

2.  Check the zinc sacrificial anodes on the boat and on your outboard or outdrive. If they are more than 50% dissolved, they should be replaced. If they have a coating of slime or growth, this should be cleaned off. Use a stainless steel brush or a non-metallic scrubber so that the zinc is not contaminated with a foreign material. New zinc anodes should meet MIL-SPEC MIL-18001. (Zinc, -0.1% cadmium and -.025 aluminum)

3.  Bare lead downrigger weights usually produce a harmful charge. Impurities that are present in the lead cause the problem. Scrap lead from auto wheel weights can be particularly bad because it contains antimony (tin). The best practice is to use only coated weights. Vinyl or powder coated weights are readily available on the market, or you can paint or vinyl dip them yourself to insulate them.

A bare lead weight will react with the stainless steel cable and create a problem voltage right in your fishing zone. To be safe, always use coated weights.

4.  Do not use a metal snap to connect the downrigger  cable to the downrigger weight. Use a nylon snap hook or connect the weight with a short piece of monofilament to insulate the weight from the wire. If the lead weight is hooked directly to the steel downrigger wire, a separate and often harmful electric field will be set up.

5. If your downrigger cable is more than 2 years old and has been operated heavily in saltwater, it may have become etched from galvanic action. This means it has been worn out both electrically and physically and should be replaced.

6. Some fishermen attempt to create the correct voltage by crimping zincs on their downrigger cable or by placing copper or other metals near their lures. This is not advisable. Often, a zone of harmful voltage will be set up somewhere in the system. It's best to keep your cables and weights as "clean" as possible and then get the correct voltage from the Black Box.

Chapter XI. Common Black Box Questions

Does it really work?

With some species, absolutely yes. It has been well proven that certain fish are attracted to a very slight positive voltage and will swim to the source of the voltage if it is in the range that attracts them.

How can I determine how much the Black Box will improve the catch on my boat? Are some boats naturally better than others?

The impact a Black Box will have on each boat differs. Some boats may have all factors favorable. The bonding is good, there is no electrical leakage and the natural voltage is just about the ideal level. In this instance, the Black Box would add very little to the catch results. Many other boats have poor bonding, "hot spot" voltage leaks, bad zincs or natural electrolysis levels that are way too high or too low. In these instances, a boat tune-up and the Black Box would help considerably. If a boat has electrical leakage or a problem which results in a high or low charge on its downrigger wires, it will have a very difficult time catching fish. The only way to know for sure if you have a problem is to go through three steps: 1) Check the bonding, 2) Find and correct any electrical leakage and 3) Measure the natural voltage. See the Chapter on testing your boat. Another factor that enters the equation is the water. A boat that measures just the right voltage in saltwater may be a little low in some freshwater. The Black Box will properly compensate for all these variables.

The fish species I am after is not listed in the book. How can I find out if it works on these fish and what setting to use?

All fish have sensitivity to electricity but some species are particularly sensitive. Most of the commercial work with Black Boxes has been done on salmon where sensitivities are well known. Some fish are known to have special electro sensor cells the fish uses to find prey. Some of these are sharks, rays, sturgeon and catfish. There is simply no data on many species of fish. As experimental test results come in, we will publish them.

Will the Black Box work in freshwater?

It may actually be more effective in freshwater than in saltwater. Because of its high salinity, saltwater creates more natural voltage. Freshwater is much more variable in salinity and mineral content. The Black Box voltage control circuit will provide the correct voltage in freshwater regardless of salinity.

The book indicates you should have an "insulated downrigger wheel". How can I determine if my wheel is insulated?

Insulated wheel means the downrigger spool is not in electric contact with the boat hull. Most downriggers are constructed with plastic spools and are automatically insulated. An all metal downrigger mounted on an aluminum boat would not be insulated. Some electric downriggers are intentionally connected to a boat's electric system (Cannon Mag series). They use an electric circuit through the downrigger wire as a means of stopping the weight when it gets to the surface. This applied voltage spooks fish. Most electric downriggers are insulated by design.

Will the Black Box work on aluminum boats?

Yes. An aluminum boat actually has an advantage over fiberglass as long as it is properly bonded and equipped with zinc anodes. The metal hull serves as the minus side of the electrolysis circuit and your downrigger wires are the positive side. With the large aluminum hull area, a wide electric field is set up in the water below the boat. With the broader electric zone, fish are attracted from a broader area. All metal hull boats have a large negative "footprint" and can have a fishing advantage.

When using the Black Box, what is the effect of my leader length or the distance between my downrigger release and my lure? If I use long leaders will it reduce the effect of the Black Box?

The electric field that attracts fish surrounds your metal downrigger wire. The further away from this wire you get, the weaker the field. Therefore for best results, you do not want to use leaders that are too long. Fish will actually swim to the wire where they sense the electric field. Leader lengths of ten to twenty feet are best. However, you must balance the affect of the Black Box with other factors that dictate leader length. In some cases (very clear water for example) leader lengths of 50 to 100 feet are often needed to catch fish. In these instances the Black Box will be much less effective.

I have a Cannon or other electric downrigger that uses the short stop feature. Can I use this with the Black Box?

The Cannon short stop feature is a system where the electric downrigger automatically stops when the weight breaks the surface of the water. This is accomplished by using the downrigger wire as part of the electric control circuit. When the Cannon downrigger is turned on, a strong positive charge of up to 7 volts is imposed on the wire. When the weight breaks the surface, the circuit is broken and the downrigger stops. The Black Box is going to impose a steady voltage of whatever you dial onto the wire (.5 volts .6 volts etc.). If a downrigger with a short stop is turned on with the Black Box running, the Black Box voltage control circuit will not let the voltage on the wire rise above your setting. The result is normally the short stop feature will be over ridden and the weight will not stop until it jams into your downrigger pulley. If the Black Box switch is turned to natural voltage position prior to turning on the downrigger, the automatic stop will work. Note: When voltage as high as 7 volts is imposed in the water, most fish will be repelled from the area. When commercial trollers are being bothered by hake or other trash fish continuing to hit their lures, they will "blow off" the trash fish by turning the commercial Black Box up to 2.0 volts.

How much power does the Black Box take? Will it interfere with my loran, VHF radio or fish finder?

The Black Box takes very little power. At full load it uses only one tenth of one amp (.1 amp). This is an insignificant amount of power relative to the other electrical devices on the boat. It puts out a small steady current of DC electricity and will have no effect on radios, lorans, etc.

Do I need to increase the Black Box voltage for extra deep operation?

If your boat has a base natural voltage reading in the range of .7 to .9 volts, most of the time you need not be concerned with depth up to 100 feet or so. Your Black Box will bring the entire wire into the range you set at the surface. If you are fishing more than 100 feet down, there can be a slight drop in voltage on the deep section of the wire. The Black Box voltage can be raised by .1 or .15 volts to compensate for this.

How does the Black Box actually increase or decrease the voltage all the way up and down the wire?

This answer is complex even for those with a good understanding of electricity. The Black Box is not actually adding or subtracting voltage from the wire. If it attempted to do so, the charge would be quickly dissipated by the electrical conductivity of the water. The Black Box works by altering the rate or level of natural voltage that your boat and downrigger wires generate. Because of this, the same voltage is being generated by the chemical reaction at all points along the wire. You will therefore have the same voltage 50 or 75 feet down that you read at the surface.

Can the Black Box be used on boats without a 12 volt battery?

Yes. The Model 1500 Black Box is designed to operate from a standard 9-volt battery, when installed. The Black Box installation is the same except the wire going to the 12-volt boat battery is not connected. The Black Box technology is available to all downrigger fishermen. It will work on any boat large or small; with or without an external 12-volt battery. If 12 volt boat power is available it is recommended that it be used so as not to run down the internal battery.

Kokanee are very sensitive to an electric charge. A Black Box works very well on this species.

Table of Contents

Chapter III. How to Test Your Boat's Electrical Charge

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Reverse or Neutral

• Thread starter jrocheleau
• Start date Sep 17, 2008
• Oday Owner Forums
• Ask An Oday Owner

I've heard conflicting views on what to do with your transmission when under sail. Should it be kept in neutral or reverse when sailing?  

What I've been told is to put it in reverse when under sail. This came from the best diesel mechanic in our area. He's the guy that works on most of the boats including the ferry and cruise boats here. I don't know if the make and model make a difference. Ours is a Universal M25. Hope this helps!  

Capt Jim24025

Depends on your engine and tranny Check with the engine manufacturer. My VolvoPenta w/saildrive says to use Reverse but my Perkins 107 manual says to use forward. In lieu of that, try them both and find out which one stops the prop from turning. You want to stop the shaft from turning to prevent excessive wear on the transmission and packing bearing. I've also been told that a stationary prop has less drag than a moving prop (but that seems counter-intuitive to me). Capt. Cook  

My spin... Right on, Cap'n... I have a Volvo/Perkins MD2030 hooked up to a Volvo MS25S saildrive. Manual states when under sail, place shifter momentarily in reverse to stop prop and then place in neutral. Cheers, Bob  

Hello All! Do you know right position of the Paragon reverse gear (Atomic engine) under sail? I didn't find it at the operation manual.  

Konstantin said: Do you know right position of the Paragon reverse gear (Atomic engine) under sail? I didn't find it at the operation manual. Click to expand

Thanks a lot! Hello Rad! My name is Konstantin. I'm from Russia and I've bought the same boat (O'Day 32)! I see that it is really rare boat and there is not a lot of information. How long you own your boat?  

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