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LowcountryData New MemberHello all, We are currently designing a 65' vessel and are having a hard time getting the recommended thicknesses needed before we can submit out plans to a Marine Surveyor. We have asked the major builders ... particularly Bruce Roberts, but without a purchase of their plans we have been basically turned away. We need thicknesses for the following areas and any others you might think of; Areas & Currently suggested thicknesses are; keel = 3/8" bottom hull = 1/4" side hull = 3/16" ribs = 1/4" topside deck = 3/16" stringers = 1/4" I see many posts in here referring to "mm" does anyone have a conversion table handy???<LOL> These we have aquired from several sources, the surveyor will not do any recommendations due to insurace reasons, so we respect that. But he did recommend this site so here we are. Our vessel most closely resembles a NY65 or a Voyager 65, that was why we wanted to get Bruce Roberts input but alas 5700$ to get the answers we want didn't seem reasonable at all. Any help or advice would be greatly appreciated, Thanks in advance, 8knots A little on the slow sideLow Country: Get on amazon.com and order Dave Gerr's book "The elements of boat strength" It will walk you through all the math of developing a scantling # for your hull then figure step by step every componet of your hull. Even a simpelton like me figured it out It is the best $24.00 you will could spend in my opinion! Your numbers seem in line off the top of my head. But you will come to understand that your ribs for eg, will have 4 figures you will need. the rib will resemble a "T" the rib itself will have width and thickness figures then the top or inside of the "T" will have a width and thickness thus 4 figures. all are derived from your SN (scantling number) that he explains in detail how to mathmaticly obtain from a small group of numbers describing your hull. A few evenings and some paper,the book and calculator will give you what you require! Good luck! 8Knots http://www.amazon.com/exec/obidos/t...=sr_8_1/103-0329688-7523015?v=glance&n=507846 This is the link- Click on the "look inside" and go to the table of contents. You will see a list of all the formulas. He does a good job of describing construction method too! 8Knots gonzo Senior MemberYou need more than just thicknesses. The design of gussets, frames, knees, beams, etc. is just as important. Each design requires a particular way of building and reinforncing the structure. Bruce Robert's price is not expensive considering the time and liability. If you have a hard time converting metric to standard, it's going to be hard to understand Gerr's or any other engineering book. $5,700 is a tiny percentage of the boat's cost. Also, any mistakes will make your labor and materials worthless. The plate thickness is the least of the complications of the design. Have you considered what the weld schedule will be? Stephen Ditmore Senior MemberI endorse what's been said. There are several approaches to metal boat design. A boat without much internal framing will require a thicker skin than one with closely spaced frames. A frame spacing of 24" is typical for commercial steel vessels. Guest Guesti think it is best to get a proper and complete set of clasification rules as the scantlings are dependent on lots of factors. this will also alow you to optimize the desig (plate thickness/ frame spacing etc.). in my experience the ABS has rules that alow reasonable "light" scantlings for sailing vessels, ABS rules ( guide for clasing offshore raicing vessels 1994 (?? not quite sure aboutthe title??). The ABS will give more freedom of choosing a construction methode and you will probably end up with a lighter design. Please be aware that local reinforcement (mast/ stays etc) are not included in the formulas but more a less to "surveyors satisfaction". most often for steel sailing yacht i see platethickness of 4 mm for the hull, as this results in a lighter construction, frame spacing will be approximately 400...450 mm. I hope this will help. YEP... I AGREE! Gonz0's point of $5700 for plans is childsplay in the big picture of constructing a 65' vessel. You will loose that much in dropped washers, welding rod left out in the rain, miscut plate because you only had 3 cups of coffee rather than 4 and all the other pitfalls that WILL happen in the construction of your boat! Thats why they cost 2 Million from a custom builder. Steve is right on the many methods of construction. I have Bruce's "Metal Boats" It was my first book on metal boats. Worth the money anyday! He does go into construction method as does Gerr. After 24 years of study I will still take my numbers to a real N/A to confirm I am not missing something. In my opinion boat design is a combination of......Math, Gut feeling, and previous experience. Those in the field will have a firm handle on all of them and the fee's they must charge are warented by the many sleepless nights they endure trying to produce the best product they can. A reputable designer will work hard for you because the design is an extension of themself, there name, and the firms reputation. For the record Gerr's book outlines all formula's in both Imperial and metric. Thanks for the soapbox 8Knots mmd Senior MemberAs a professional designer, I can't help but agree with 8knots' choice in having numbers checked by another qualified designer, and Gonzo's viewpoint on the cost of design services as a percentage of the overall constructions costs. To risk being unnecessarily dramatic, consider the problem in this light: Will the warm feeling of saving a few grand in design costs comfort you when you are in the middle of an offshore passage with the kiddies bunked down for the night, and as you are checking the latest weatherfax you realize that you will not be able to outrun that storm front on your tail before you reach the nearest safe port. Are you really confident in those structural calculations that you made those many months ago? After careful & serious consideration of that question if you are not comfortable, call a designer with some experience in steel construction. A design check by a pro is good insurance and not really that expensive in the larger scheme of things. Your life may depend on it. SuperPiper Men With Little Boats . .Because of the discussions on this thread, I have ordered Gerr's book. As 8knots suggested, I read the first 2 chapters on-line. I have a mini-pocket-cruiser. With each glass project I wonder: did I apply enough layers? did I extend the tabbing far enough along the hull or bulkhead? is the core thickness correct? And, IMHO, $5700 is a lot of money. If $5700 is a lot of money, then building a 65 footer is way out of your budget. I also think that prospective buyers are sometimes too eager to dismiss the amount of work a proper desing takes. Three weeks of my time is worth every penny of $5700. Also, I am liable for mistakes. rjmac Junior MemberDitto....Ditto..... If you are uncomfortable with $5700, 65ft is out of your range....., you need to be realistic, and not meant to be rude. Your Own Design If you don't know how to calculate structure you may want to rethink doing your own design. Do you know how to calculate stability? Do you know how to calculate powering? Also note that Gerr's book is really only for understanding strength, not for actually doing it, especially for such a large boat. In actual design practice, the internal structure and its spacing is a trade for plating thickness - more closely spaced frames = thinner plate and vice versa. However, closely spaced frames tend to have more labor, so it is a trade requiring some knowledge. Gerr just suggests a standard thickness and spacing which might not be right for a given project. Also, Gerr's book has no official standing, so a given surveyor/underwriter may not accept it. Only class rules or ISO rules have the necessary buy-in from all stakeholders to establish a real standard. Gerr's and other books that give scantligs and construction techniques have to be checked against whatever rules apply. It takes knowledge and experience to decide which way to go. For example, a rule may call for more closely spaced frames; this may allow thinner plating. Another rule may specify fireproof resins in the engineroom; they have different characteristics than regular epoxy and are not compatible with Dynel. I think that most of us around here (at the forum) we are in the idea that we can help each other and find interesting information all of excellent topics related to boats but when it comes to this kind of "i'm building a 65' boat but...i don't know what scantlings use and $5700 for set of drawings is too much!....please, FORGET IT! is not worthy to keep having posts toward this, please leave alone this post and let's help people that really value the work and responsability that is to design a boat, and help the ones that need some advice. Glad to be here in the forum and be able to help. Take it easy "guest". The forum is open to all questions about boats. Lowcountrydata is trying to get information and is welcome to it. Steel plate for small steel boatsAluminum vs carbon steel for supporting chainplates / shroud load calculationGeorge Sutton steel schoonerBrent Swain 26' Steel YachtSteel mastsBoden "Elizabeth" Steel KetchCheap steel yacht multi chine in BulgariaLiza Jane, steel 20' sailboatWatts steel ketch- No, create an account now.
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Steel for Sail and PowerS teel ships are the backbone of world trade, and navies around the world maintain their allegiance to the metal. Like-minded builders of smaller commercial fishing boats, tugs and barges also favor the iron/carbon amalgam. So why do we see so few recreational power and sailing vessels being built from what’s arguably the strongest and one of the least expensive boatbuilding materials? Before attempting to answer, it makes sense to take a close look at what steel has to offer. Riveted iron was the first step in a ship building renaissance, a trend that gave white oak and spruce trees a bit of a reprieve. Eventually, carbon was added to iron increasing its tensile strength and stiffness. At about the same time, welding expedited the building process and steel plate was cut and shaped using highly directable flame heat from oxyacetylene torches. Today, steel can also be cut with laser, plasma, waterjet, and saw blade technology. Metal workers bend hull plate over steel frames, tack weld the plate in place and eventually carefully fuse all the seams together. Stick welding became a highly prized craft essential to how frames were tacked in place and plate-to-plate seams were joined. At the heart of the process is the welder’s electrical transformer, a tool that turns AC current into lower voltage higher amperage DC current with the capacity to melt metal. Its lower voltage dissipates the shock hazard. Electrical welding harnesses an intentional short circuit. The positive and negative leads meet at the point where the welding rod touches the grounded plate. A key factor in welding involves smoothly working the rod across the seam allowing the high current to momentarily turn both the rod tip and plate into molten metal. When the steel “weld pool” cools, the resulting joint is as strong or even stronger than the hull plate itself. Pluses and minuses Mild steel, as a material, has a long list of desirable attributes along with a couple of potential showstoppers. On the plus side, resides toughness, malleability, and isotropic strength (equal strength in all directions). The net effect of these attributes includes abrasion resistance and a structure that reacts to point loads by deforming rather than tearing. It’s also the least expensive of modern small craft building materials and is relatively easy to repair. The build process can be expedited using computer aided design (CAD), numerically controlled cutting (NC) and laser, plasma or waterjet cutters that steel suppliers use to provide pre-cut hull plating that fits together like puzzle pieces. Steel boat designer Michael Kasten has found that this service can cut building time of a 45-footer by up to 40%. Rust is the enemy of every steel boat owner. Adding carbon to iron increases the metal’s strength but also ups its tendency to oxidize. As steel begins to corrode a powdery, rufous-colored scale quickly grows into flake-like layers of rust as the material’s strength and stiffness disappear. Steel ships are designed with a specific percentage of added plate thickness to account for corrosion over the vessel’s design lifespan (usually 20 years). Small craft designers can’t afford to add the weight of thicker plate and the design process seldom incorporates such corrosion compensation. Instead, contemporary coatings, meticulous preparation and application techniques will do a very good job of holding rust at bay. Streamlining steel boat construction defies the round bilge smooth curve status quo. And one of the biggest challenges involves generating hard chine aesthetic appeal and maintaining bilateral symmetry. In short, the challenge is bending flat plate into a functional hydrodynamic shape with enough aesthetic appeal to draw a sailor’s eye. In years gone by, master craftsmen struggled to twist and cajole steel plate over round bilge frames that incorporated compound curves galore. In many cases, several hundred pounds of epoxy filler had to be pasted to the hull, troweled out and sanded smooth with “long boards” to mimic the fairness of a timber or FRP hull. Today, single chine, multi chine and radius chine designs prevail. They are designed to minimize the slab-sided look and are much easier to build than a complete round bilge boat. The FRP production boat industry has helped by following automotive trends, and adding a chine to their racers and cruisers. Fine tuning stability The design challenge also includes how the significant weight of steel is handled. When it comes to vessels less than 50 feet, weight distribution becomes an even bigger issue. For example, to lessen weight above decks and still minimize deck flex, a designer must use thinner plate, 10- or even thinner 12-gauge steel. This requires shorter spans between transverse and longitudinal support or a switch to stiffer Corten steel. Some builders even switch to aluminum above the sheer, a weight saving alternative that ups costs and adds complexity. This metal transition requires the installation of an explosion welded bi-metallic strip that’s composed of aluminum bonded to steel. It allows a fabricator to conventionally weld one side of the junction strip to the hull’s sheer and then TIG or MIG weld an aluminum superstructure to the opposite side. Welding aluminum requires an inert gas to shield the arc, and the plate is harder to weld but easier to cut. The surface can be left uncoated, it will form a self-protecting, lightly oxidized layer that abates further oxidation. The steel hull, however, must be blasted, primed and painted inside and out. And as Michael Kasten professes, “clean and grit blast the surface, apply epoxy and avoid using sprayed-in foam insulation.” The all-steel alternative can also be designed as a seaworthy vessel if careful attention is paid to weight distribution and the height of the superstructure. Payload location can also be a vital consideration. During the design process, every effort should be made to place machinery and integral tankage as low in the bilge as possible. Chain, batteries, and heavier equipment should also reside in the dry spaces below the cabin sole. If a power cruiser is to be an offshore passage maker, these vertical center of gravity considerations rule out the double-decker riverboat look and it’s also wise to avoid perching a sizable runabout and lifting crane on the top deck, aft of a heavy flybridge. A fringe benefit found aboard lower air draft power cruisers is that it places cabin space closer to the waterline where there is less effect from pitch and roll and windage is lessened. Sail and power Over the last 40 years I’ve kept track of a small but hearty 45-foot tug/work boat built by Gladding-Hearn Shipbuilding in Somerset, Mass. Dragon belonged to a friend of mine and played a central role in his marine construction business. And whether he was pushing a small crane barge, towing a load of pilings up and down Long Island Sound or when the vessel was loaded up with a sunfish, whitehall rowboat and provisions for a summer family cruise to Block Island — Dragon fit the bill. For decades Captain Jim and now his oldest son Eric have followed a regular rust abatement routine. Their anti-corrosion strategy included regular inspections of hard-to-get-at confines and never painting over rust. The grinder and wire wheel effectively abraded small spots but grit blasting to “white-metal” status was used when appropriate. Their painting preference revolved around PPG Ameron products. High on their to-do list was changing zincs and meticulously servicing the trusty old Detroit 6-71 diesel. Steel sailboats and power cruisers still hold justified appeal, but it’s important to understand what ownership entails. This is especially true for those considering a DIY build of a steel cruising boat. A good starting point is a thorough review of both Bruce Roberts and Michael Kasten’s in-depth online commentary. There’s plenty of valid detail about building metal boats, both aluminum and steel. Those with experience in welding and metal fabrication have a very significant head start and finished hulls will reflect those who learn metal work during the project and those who start out with essential fabrication skills. If you’re considering purchasing a steel cruising boat it’s essential to engage a skilled, metal boat-versed, marine surveyor. But before that develop a clear vision of what you are after. A handy way to compare vessels is through the use of parametric analysis. It’s basically, a straight forward spec comparison among two or more vessels and recognition of how the numbers relate to underway characteristics. Two hulls compared In this case I’ll compare my own well-seasoned 41-foot Ericson (18,000 pounds displacement (six-foot draft, 10’ 8” beam, 8,200 pound ballast, 750 square foot sail area) with a classic round bilge, steel 37-foot Zeeland Yawl, (18,000 pounds displacement 5’8” draft, 10’ beam, 5,700 pounds ballast, 550 square foot sail area). Though the two boats’ displacements are similar, the Zeeland Yawl’s working sail area is a lot less. This is likely due to a lower righting moment (ability to resist heeling). A further indicator of this diminished stability is the lower ballast/weight ratio, even though the displacement numbers are the same. The net result is a bit less ability to recover from a deep knockdown or capsize. The designer saw this and responded with a smaller sail area that induces less of a heeling moment. In real world terms this means that the E-41 would be far more efficient sailing in light air as well as more likely to avoid a knockdown, even when both boats are deeply reefed. But when it comes to sailing higher latitudes with bergy bits floating by, or fetching up on an uncharted rocky shoal, the Zeeland Yawl’s Corten steel hull wins hands down. The reason welded steel construction has dominated the maritime industry for decades yet made only a slight ripple in the realm of recreational small craft construction is multifaceted. In part it’s due to the production efficiency of molded FRP boat building, the ongoing concern over corrosion, plus the reality that most recreational craft aren’t put to the same rugged use as commercial vessels and work boats. However, for those who sail or power cruise well off the beaten path, steel hulls are still held in high regard and to rank number one when it comes to abrasion resistance and survivability in groundings, collisions, and other blunt force trauma. n Ralph Naranjo is a circumnavigator and the author of The Art of Seamanship (International Marine/Ragged Mountain Press). | | | Find anything, super fast. - Destinations
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We don't have any additional photos of this yacht. Do you? Nord Star Specifications- Name Nord Star
- Model Custom
- Class M-SP, Russian River Register
- Hull NB O-110-1
- Hull Colour -
- Naval Architect Moscow Shipyard
- Exterior Designer Moscow Shipyard
- Interior Designer Moscow Shipyard
- Length Overall 34.6m
- Length at Waterline -
- Draft (min) -
- Draft (max) 1.6m
- Gross Tonnage -
- Cabins Total 4
- Hull Configuration -
- Hull Material Steel
- Superstructure -
- Deck Material Teak
- Fuel Type Diesel
- Manufacturer Caterpilar
- Power 385 hp / 283 kW
- Total Power 385 hp / 283 kW
- Propulsion -
- Max Speed -
- Cruising Speed 11 Kn
- Fuel Capacity -
- Water Capacity -
- Generator -
- Stabilizers -
- Thrusters -
- Amenities -
- Yacht Builder Timmerman Yachts No profile available
- Naval Architect Moscow Shipyard No profile available
- Exterior Designer Moscow Shipyard No profile available
- Interior Designer Moscow Shipyard No profile available
Yacht SpecsOther timmerman yachts. Dyna-Ski Boats custom builds outboard powered water ski boats for recreational skiers and show ski clubs. We have customers all over the world including Malaysia, the Caribbean, Moscow, Russia, the Cayman Islands and Canada. This blog is used to keep readers informed about what is going on at Dyna-Ski and answers questions that are frequently asked. You can also visit www.dyna-ski.com for more information about our boats. Contact Dyna-Ski at [email protected] or call 715-854-7501. Wednesday, August 13, 2014Tracking fins. No comments:Post a comment. |
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Above 45 feet and steel structure begins to come into its own. Above around 50 feet, a steel hull can actually be quite light for her length (by traditional cruising vessel standards). ... with 1/8 inch thickness being a more likely lower practical hull thickness limit. As a comparison, the minimum thickness for other materials (mainly due to ...
Re: thinkness of hull steel. As one of the other posters said, steel thickness typically is reduced higher on the hull. On a 60 footer the keel bottom will probably be 3/4", the keel sides will probably be 3/8" to 1/2", 1/4 to 3/8 on the bottom, 3/16 to 1/4 on the sides, usually I'd expect 1/8" on the decks.
The 10M Tucker design steel boat I built has thickness of 4mm plate for the hull, 3mm for the deck, 6mm for the sides of the twin keels and 10mm for the keel feet and tops. This was what I ordered from the steel supplier. When surveyed it was found that the decks and the hull thicknesses were about 10% thicker than this.
Posts: 2,103. Boy, I'm not sure where the idea that 4 mm is sufficient for the hull of any boat over 30 feet or so. Delfin is 1/4", or 6.4 mm, and prior to fairing, showed deflection in the bow plates with the ribs on 18" centers. If the steel was Corten, maybe 4 mm would work, but Corten steel has other issues.
That said, small steel boats are generally stronger than larger ones. Here are some thicknesses of steel hulls I had built in the past; Tom Thumb 24: Hull = 3mm, Deck = 3mm - Frameless design - multi chine. Tom Thumb 26: Hull = 3mm, Deck = 3mm - Frameless design - multi chine. v/d Stadt 34: Hull = 4mm, Deck = 3mm - Frameless design - multi chine.
But that's NOT what you get on a standard hull survey. But back to the question about hull thickness foe a moment. Most smaller yachts are 10gage steel. That's a tiny bit thicker than 1/8". Larger boats tend to be 3/16". Then you get boats with 1/4" keel and 3/16 topsides. I have seen a 52' boat made of 10 gage steel.
The process starts with clean, shot-blasted steel plates arriving at the factory gates. The thickness of steel used ranges between 4 and 6 millimeters depending on where it is used and the size of the yacht to which it is destined. Linssen cuts these steel plates to shape using a CNC plasma profiling machine.
Indeed, the plate thickness for small-boat steel hulls are somewhat heavier than required for basic strength to allow for corrosion, the corrosion allowance. A good rule of thumb is that a steel hull will loose about 0.004 in. of thickness every year. A well maintained and properly built steel boat will do a bit better than this in most places.
GRP is far superior to steel in terms of weight. For boats up to about 40 feet, it is also superior to aluminum, since aluminum has a minimum thickness of about 5mm making smaller boats heavier than their GRP competitors. Above the 40-foot mark, the tide can turn, and aluminum may be lighter than GRP, but it depends on the exact construction.
Please be aware that local reinforcement (mast/ stays etc) are not included in the formulas but more a less to "surveyors satisfaction". most often for steel sailing yacht i see platethickness of 4 mm for the hull, as this results in a lighter construction, frame spacing will be approximately 400...450 mm. I hope this will help.
Steel boat designer Michael Kasten has found that this service can cut building time of a 45-footer by up to 40%. Corrosion can be kept at bay by proper maintenance and modern coating technology. Rust is the enemy of every steel boat owner. Adding carbon to iron increases the metal's strength but also ups its tendency to oxidize.
The cost of a steel hull is very competitive when compared to other materials and the price of steel has remained constant for several years. The cost of the materials alone to build a 35 to 40ft yacht hull and deck is around £4000.00 ($6400.00 US) (UK prices in 1998). This makes the cost of a steel hull particularly good for the home builder.
Ost Power 20 sport fisherman or general purpose boat. DUDLEY DIX YACHT DESIGN. Ost Power 20 . Versatile new powerboat ~ Production builder ~ Modern styling ~ Sportfisherman ~ Diveboat ~ Patrolboat Ost Yachts website. MENU ... Hull draft - 0.33m [1' 1"] Displ - 1425kg [3140lb]
Motor yachts, super yachts, CAD-CAM for naval architect. We like shipbuilding ... Workshop hull drawings : Valdai-1. Valdai-2 . Basic project /code: PC870 /Valdai-1. Modernization project / yacht's name: ... Material of hull/ superstructure: Steel /ALU . Beautiful photos of the yacht's interiors here: ...
Hull Configuration - Hull Material. Steel Superstructure - Deck Material. Teak Decks NB - Engine(s) Quantity. 2 Fuel Type. Diesel Manufacturer. Caterpilar Model ... Timmerman Yachts No profile available. Naval Architect Moscow Shipyard
The older boats had a cast aluminum tracking fin. They are no longer available. We switched to a composite tracking fin a long time ago for several reasons. The main one being a composite fin will break off and do less damage to the hull than a metal one will. Easier and cheaper to replace a tracking fin than to fix a hole and replace a fin.