History: Making a hull from wood models

Discussion in 'Boat Design' started by newcat, Jun 2, 2014.

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  1. newcat

    newcat Previous Member

    I today... start on a project i have planned for years.

    I want to design a cat like the Wharrams, but with high performance hulls.

    I want to design the hulls using old techniques. I want to carve out the shape and water test. How did the old designers go about doing this?

    My plan (very beginning) is 40'... Very high performance hulls, open deck (Wharram like) Pre Preg glass, Foam, carbon box beams, Wharram like Lashings.

    I want to start carving hull shapes, not worried about massive inside room,
    i want speed. Boat to be built to sail the trades, S. Pacific.

    Any suggestions on how to start, shapes, ideas, etc etc would be great.

  2. messabout
    Joined: Jan 2006
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    messabout Senior Member

    Newcat: You are about to shoot yourself in the foot....or worse. The questions you have asked suggest that you are less than entirely familiar with design processes.

    Get some plans from a professional NA or acknowledged designer. The price that you pay will be far less than the grief that you will get from a self design.

    If you want to toy with the design process you can, of course, build some models. The old fashioned way is with "lifts". That is a bunch of thin planks stacked one atop the other. Now cut, carve, plane the stack into a shape that you like. Separating the lifts and tracing the profiles will give you waterline configurations from which you can derive buttock profiles. That is the way the old timers, like the Herreshoffs did it. They were professionals with vast experience, however.

    The inexperienced are well advised to do all the carving for fun, not for design purposes. If you aspire to cruise the South Pacific or wherever, it will be well for you to build to a proven design that has a fair chance of delivering you home safely.
  3. newcat

    newcat Previous Member

    Thanks for the info. on the lifts' i will start to research that.

    As for the other, not so sure i'm worried out begin able to design two good hulls to lash and sail. There are thousands of views on proper hull design, truth is, all have their strength and weaknesses. I feel i can can design a pair of hulls that will be safe, fast. Will they be polished like some Nigel Irene designs, no, but nether were the boats that did sail around the world, 1000's of years ago..
  4. upchurchmr
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    upchurchmr Senior Member

    One of the best ways is to look at something already made that works and start from there.
    Look for information on a McGreggor 36' Catamaran.
    Make a model of that boat then make whatever you want personally.
    Compare their performance at the model size and see if you improved things.
  5. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    1000 years ago there were many designs that were "polished". Models are the evolution of thousands of years, and they use the best materials and techniques available at the time. It is arrogant to dismiss technology that has been proven in everyday use. The way you describe the structure of a multihull as something you can just lash together indicates a lack of knowledge.
  6. newcat

    newcat Previous Member

    As is comparing a new design idea that's tested 1 year, too one that has been tested over 1000s...Two hulls, beams, center deck, lashings is exactly what i'm going to do. I asked about designing the hulls the old fashion way. It worked then, it can work now.....The info. i'm looking for is not, fire up yacht-design software. Anyone can do that...and claim to be smart doing it too!
    I will study the basics, and do it the old way.

    I have changed my mind a little on the boat:

    I have taken the length down to 32ft
    I'm going to use twin junk sails, one each hull
    The center deck area is going to have a stow away (in deck) tent system. Pop up...
    I will build the boat from foam and pre preg S glass under vacuum.
    Beams carbon box
    Mast carbon (built by me)
    Decks, bamboo
    Tent Cuben fiber material
    Tent supports, like a high quality alpine expedition tent. Geo Dome type, that stows below.
    Below is a head Air compost, Taylor stove, all lighting is kerosene

    14hp Beta
    Large tank (as large as it can be without effecting the sailing)
    Upgraded alt. for charging
    Big battery bank
    designed, floating solar panel array.

    So in short, a very modern hull shape, fast performance, with spartan comforts, for no rush, long distance voyaging.

    Any ideas on a modern hull shape, that allows full beaching, would be appreciated. Got an idea done? let me see it! Maybe i will build it, as long as it fits with the theme of this boat, flush top decks, fast modern hulls etc etc

    Something like this, with flush decks, junk rig, is the idea. Modern and classic in one boat. Modern hull shapes, classic everything else. http://multihulldesigns.com/underway.htm
  7. upchurchmr
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    upchurchmr Senior Member

    Keep showing (or start) your design.
  8. messabout
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    messabout Senior Member

    Newcat; no one here is disposed toward belittling another person, so do not take the nay saying as a personal affront.

    You seem to have your mind made up about some features that are less than complementary. You want fast hulls but you want junk sails. That is a combination that is questionable. You intend to put them on opposite hulls. If so your windward performance will suffer. Junk sails have a lot of sheets that need a wide sheeting platform but you will not have that lateral space on one side of a slender cat hull.

    You want big tankage but with a fast cat every pound counts. Weight is the enemy if you want speed. Then there are the batteries, the gen set, and all that sort of thing. As you design your boat you will be obliged to account for every last pound of weight that she will carry. The hulls have to support all that weight and so you have to calculate and design the displacement accordingly.

    Do you think that a tent will hold up in a gale? Just about any storm worthy of being called a storm, will send tons and tons of water over the topsides and the tent will be gone in a New York instant. Not too far from DC you can get into the Gulf stream where a brisk nor'easter will pile up waves 30 feet from crest to trough. You won't like that and neither will your boat. If you are going to cruise then you can be assured that sooner or later you will encounter that kind of weather.

    A boat held together by lashing will not survive. Some of Wharram's early stuff proved that rather quickly. Arthur Piver also tried the lashing route and abandoned it forthwith for good reason.

    Sorry to pick on your ideas, but they do need a full airing in the interest of your boat and possibly even your survival.
  9. newcat

    newcat Previous Member

    I think all your points are valid. Everything i have read says duel junk rigs are superior too more modern rigs in downwind sailing. Most of my planned sailing will be trade-wind. I don't see myself sailing windward enough to justify a more modern rig short comings in trade-wind type sailing.

    I clearly stated tankage large enough, but not so large that it effects the boat more then normal negative. No gen set, and the engine is a long shaft 14hp Beta, not that heavy in the first place.

    I also clearly stated that the tent is a stow away tent under deck. It is used for long periods of time at anchor. Assuming i would have a geo dome tent up in 30+ winds,( or anytime) while underway, is silly...

    If i sound rude, except my apologizes, i asked a question about hull design of yesteryear, not a request for lectures on stuff i have known for 20 years.
  10. newcat

    newcat Previous Member

    I will, once i learn how to plan out hulls. :D I can build them (Some Pre Preg Carbon experience) I just need help with the design of the hulls.

    I want Gunboat like performance hulls, with a flush deck. Not sure if anyone has tested an ultra high performance hull shape, built fairly light, with duel junk rigs in the trades.
    I bet she will be a rocket ship. I was thinking Crab Claw, but from what i read, single crab sail is better then two...which equals one huge crab sail! So i figured 2 Junks will be much better for no rush sailing, in the trades. Still not even close to rig selections, A single crab might still be the answer, i don't believe anything will lift better then a crab.
    Still much thinking to do for sure, but right now its hulls.

    Here is a Wharram i like, if i built one, this would be it!
    With updated tiki lashing/beams.

    Attached Files:

  11. rwatson
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    rwatson Senior Member

    The kind folk trying to let you down gently have yet said that the Junk and Crab claw sails are so inefficient that it wont matter how well your hulls are designed to be "ultra high performance hull shape", it will sail like a dog.

    Where did you get the idea Crab Claw sails can point well ??
  12. gonzo
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    gonzo Senior Member

    newcat: If you want to do it the "Old way", spend years apprenticing and slowly learning the trade. The new way is faster and less painful, but requires more technical learning.
  13. newcat

    newcat Previous Member

    Two more that don't have an answer for the original question, and have a life long need to sound smart on an internet forum. One of them even went so far, he dreamed up a statement i made, then asked me why i think it! :p
    "when did i EVER say i think a crab will go to windward better then ......"????
    Please quote me!

    Only thing i said was it has more lift

    I'm not a marine architect, you got me! That's why i'm on this forum asking questions, Please just get lost if you cant answer the question, i don't care
    what your opinions of my idea are.....Not even a little bit. I want to know how to design a hull from wood, to test myself.
  14. Richard Woods
    Joined: Jun 2006
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    Richard Woods Woods Designs

    By "Wharram like" do you mean open deck or a deep V hull or really like a Wharram???

    I would think the early builders who hand carved wood models and scaled them up probably built one model and full size boat, then another to refine it, then another....Over hundreds of years as you say

    If you want to do it right first time it will be challenging. I wouldn't attempt it

    Will you be building the boat just with hand tools just as they did hundreds of years ago, or use power??

    Once built will you use modern equipment like wire rigging, dacron sails, gps, an engine, good drinking water, take fresh food - so no scurvy? Or rely on what they did hundreds of years ago, back when seafaring was far more dangerous and unsafe than today. Not being sarcastic, just asking if you plan to do everything like old timers did?

    In my experience if you sail downwind you will eventually reach a lee shore - then what?

    Richard Woods of Woods Designs


  15. gonzo
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    gonzo Senior Member

    We got answers that you don't like. It boils down to: it takes a lot of time and effort. You don't want to put the necessary effort into the project. It is not about a life long need to sound smart. We put decades of work and study to get where we are and continue working at it. If you think you know better than us, build the boat and go sailing; prove us wrong. Calling names is not a convincing argument.
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