Swath Boat building Plans

Discussion in 'Boat Design' started by blackdaisies, Sep 1, 2008.

  1. blackdaisies
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    blackdaisies Senior Member

    There are tons of boat building plans on the internet, but I found none for Swaths. They are the most durable boat for rough water, stable on water, energy efficient with a 60 percent increase in mileage in fuel compared to other boats, fast, and look as easy to build as a pontoon. Can I assume any pontoon pattern can be used for a pattern? Does anyone know the measurment between the pontoons and the walls leading up to the boat platform? I looks like for a very small concrete boat, the pontoons would be 1 foot wide and there should be a 1 to 2 foot rise from the pontoons to the platform.

    Also what is the greatest length of boat for this type of boat that one sail can move through water efficiently without a motor?

    If anyone would even take a guess, I would appreciate it.
     
  2. yipster
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    yipster designer

    in a small model test you can find the principal idea but swath's are not ment for still waters and structuraly it is a tough boatdesign were concrete wont work as building material. ah, a sail, how nice but have you considered the exesive heeling in smal waterplane area displacement twin hulls? read more on swath under the search button!
     
  3. clmanges
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    clmanges Senior Member

    Blackdaisies, I was looking at this just yesterday, and I wouldn't put a sail on one; one of the problems is their dangerous behavior when heeled.

    You ask about foot-wide pontoons, but it's a meaningless question, since you haven't said anything else about the boat -- length, width, displacement, other dimensions.

    As to materials for the pontoons, large plastic pipe is a good place to start looking, but do the search, as Yipster says, and you'll get a better idea.

    Curtis
     
  4. blackdaisies
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    blackdaisies Senior Member

    I wanted to be within trailering width, very small at 8 foot wide and 33 feet long because it will fit the multi hull trailer I plan to buy before I even start thinking to make this. This is a beginner project. There is more stability on the ocean on a swath. Catamarans are supposedly more able to handle harsh weather and with the weight put in proportion can act like a swath, but the swath is more stable in the waters.

    Which do you think is more important on a small boat on the ocean? Better harsh weather handling or better stability on the ocean water? I know a small boat of less than 36 feet would never be good for ocean traveling. The farthest I could possibly go is down the Mississippi and if there's time into the gulf and on the ocean. I want a good boat for both waters.

    It looks like the pontoons would be 2 feet wide and the wall heading up from the pontoons would be 4 feet long, then the platform would be added. The boat would have to be heavy enough to make the pontoon sink 4 feet and then the platform could be up to 7 feet? Tell me if this sounds off.

    On the internet I've seen huge swaths with three floors, but the swaths are probably 10 feet wide or at least 6. The boat itself looks like a huge rectangle box shape long end vertical, so its a wonder how they don't fall over. I would imagine self righting them would be hard.

    Hollow concrete pontoons wouldn't be that hard to make even for a beginner, but how would the pontoons do holding all the weight of the boat from the bottoms? They may crumble if they are kept on a trailer.

    If I had a company that just sold easy do it yourself plans for mini small swaths, I wouldn't have a problem. I just thought there would be something out there on the internet already about one that size.

    Thanks for the advice!! I appreciated the help!
     
  5. Infinitus
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    Infinitus Junior Member

    This is a topic I, too, am interested in. Are there any technical design books on SWATH boats?
     
  6. masalai
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    masalai masalai

    That wont be nice - have a look at my gallery - I had a go at a power boat - made a model after going for a trip on the 30ft C10 designed by Robin Chamberlin (about 2 ft hull beam best for coastal or semi sheltered waters.

    Have a read of The Coastal Passage about 2 editions back - all about "Foreign Affair" which was motored from Brisbane and back filling up twice and also driven across to New Caledonia and Vanuatu (14 meters LOA) http://www.thecoastalpassage.com/ for the New Caledonia trip
    http://www.icecat.com.au/objectives.htm for the story - look at all the links for the full story. of the trip Brisbane to Tasmania (Hobart)

    there is a 12 metre version being built in Brisbane now... this is not for amateur design or build...
     
  7. blackdaisies
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    blackdaisies Senior Member

    http://www.sailingcatamarans.com/wiz.htm

    I think it would be better to stick to something already available. There is no current plans available on the internet for swaths the size of a small houseboat or mini cruiser. The only thing that comes close to a trailerable 8 foot clearance is this one when folded.

    http://www.dixdesign.com/3fold6.htm

    It's a trimaran that folds in 4 positions, one for storage in the dock, one on the trailer, one in its full position, and a self righting position, but it's for somewhat protected waters.

    I've read that the way they are building the hulls bigger or deeper, they might be almost the same as a swath, but a different shape altogether. I think that's the closest I will get before plans are available for a swath for mainstream beginners on such a small boat. These boats are usually over 60 feet.
     
  8. clmanges
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    clmanges Senior Member

    I think there's a good reason for that. Near as I can tell, SWATH design has a rather limited range of applications, and none of these seem to be recreational.
     
  9. blackdaisies
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    blackdaisies Senior Member

    They are for stabilizing the boat mostly, but are better than a conventional boat on the ocean. It's mostly been used for platforms for drilling oil and diving. The size of the boats can be smaller and still be stable on the water. Normally on a small boat you will be bounced around. They were created so they could use smaller boats to do jobs normally done on larger ones. A ship is much more expensive than a swath boat, so it must have saved a lot of money.

    That is why I would think if you compared a 36 foot monohull's stability and sea worthiness to a 36 foot swath, it wouldn't compare very well. Plus the swath is faster. It's more expensive to build, but if you do it yourself for a small boat, it would be worth the extra money. Even to buy one, it would be worth the money.

    I have only read good things about swaths and catamarans except they cannot read the wind very well. In a traditionally boat you get better sailing because of it.

    I wish I could get this same plan, but in a longer form. The trailer will only take up to 33 feet, but this plan is for 22 unless it comes with a way to lengthen the hulls. The small 8 foot width is important to me anyways because I want to use normal means of trasnprotation to get the boat in the lake. I know the "Wizard" is small enough a fist time builder could get it done.

    They should have more plans available for swath boats. I know they are fairly new, but they would go like hotcakes if they were introduced to mainstream boaters for better platform boats. I'm sure a fisherman would love the stability more.
     
  10. masalai
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    masalai masalai

    33 ft long and 8 ft wide sounds like an impending disaster and to put it bluntly f***ing stupid, as that beam = no stabulity.... just look at what has been built and demonstrated to work....
     
  11. blackdaisies
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    blackdaisies Senior Member

    I definitley don't know much about boat building, but canal boats are somewhat that size, large canoes, and Gondolas are similar too. I have also read the longer narrower boats are better on the water. Not to say my dimensions are right because I don't know myself for sure, but they seem to be in the same category and there are many out there. Maybe not on those dimensions, but some are.

    http://en.wikipedia.org/wiki/Narrowboat

    [​IMG]

    The plan I mentioned opens up to be about 13 feet. I want something like this canal boat, but see it as adding those underwater swath pontoons to make it more stable.
     
  12. masalai
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    masalai masalai

    like a wooden horse.... wont work....:D:p:D:p
     
  13. blackdaisies
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    blackdaisies Senior Member

    What do you think of canal boats at all? With Hydrofoils in the back? Install some swath pontoons underneath them? That would be the same thing as what I was talking about.

    Here's an oversized canoe that does well.

    http://www.blackfishwilderness.com/canoebuild1.htm

    http://www.blackfishwilderness.com/canoehistory.htm

    I guess if I want to make a safe boat a long ocean going boat it will have to be with outriggers on simple longboat type patterns. The outriggers can be swaths? That sounds more solid and it would work.

    These are ocean going rowboats, so if they can make a boat capable in such a small area, a swath or cheap imitiation of a swath should be worth a shot.

    http://www.row4water.org/index.php/view/3

    There are those boats that I don't know the name of that have those long poles attached to the bottom of their boats with a pontoon like shape. They say those are for stability. Have you ever heard anything about those?
     
  14. Munter
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    Munter Amateur

    With due respect, I think you need to do a lot more reading before starting a swath project. Its easy to see some of the advantages of that type of craft while forgetting the disadvantages. Start with a consideration of the centre of bouyancy and the center of gravity and think about what happens when the boat heels. Also think about the ability of a swath vessel to handle changes in load and trim.
     

  15. blackdaisies
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    blackdaisies Senior Member

    http://www.swath.com/Tri-hull1.htm

    This gives more techinical information on how the typitcal swath and the trimaran type swath behave. But I'm reasearching the questions you asked and will have some more information about them. I just thought this article was worhty of this thread since it give most of the vital information about swath building.
     
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