1 man homemade swath for flyfishing

Discussion in 'Boat Design' started by 32ballew, Dec 28, 2014.

  1. 32ballew
    Joined: Dec 2014
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    32ballew Junior Member

    I'm not a engineer or a boat builder. I'm a Pipefitter/welder/fisherman. Looking for some help. Sorry if this has been discussed in other threads. I can not find it.

    I can't sit in a float tube due to a bad back. I want to build a small swath boat I can fly fish off of in the many resivours in Eastern Montana.

    The wind is the issue. Blows my river runner all over the place. Drift boat wouldn't be any better. Doesn't need to be fast but stable in 2'-3' waves.

    My plan is to build a 8' x 12' flat deck with 4 submerged pontoons (3 times the diameter) made of pvc pipe. Diameter and length determined by total weight of the deck, myself, batteries and gear etc. Planning on powering it with a Minnkota terova bow mounted trolling motor. I've got an idea to build a frame for the pontoons that can be raised and lowered for transportation.

    Will it work? Any advise or foreseen problems would be greatly appreciated.
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    Can't see how "swath" would be any good in a small fishing boat, you move to one side or end of it, and it will tilt considerably. You can set a drogue to slow your drift rate in any boat.
     
  3. 32ballew
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    32ballew Junior Member

    Just thought it would be affected by the waves less with the below surfice displacement and the low profile flat deck would be less for the wind to push around. The extreme tilt was one concern. Figured I'd build it heavy so my weight would be less a factor. Think it would tip easily?
     
  4. 32ballew
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    32ballew Junior Member

    Haven't had much luck with a wind sock.
     
  5. Ad Hoc
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    Ad Hoc Naval Architect

    Making the Swath for your SOR is relatively easy. It would be 'tuned' to your wave spectrum.

    The difficulty will come, as already alluded to above, the list/trim. Being such a small vessel, it'll be extremely sensitive to any movement....not to mention whether it will carry you on the displacement available.

    A Swath of your size would be circa 500kg max, all up displacement, including you and your bits. Thus can you get your structure, your ballast system your means of propulsion etc....all up for less than 500kg?

    If so, then there is hope. BUT....being so small, any slight movement would incur high list/trim...so, you would need to investigate if you can sit & remain fishing and afloat with such sensitivity.
     
  6. JRD
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    JRD Senior Member

    Ad Hoc, I am curious as to what size of Swath is normally considered the practical minimum? The only small Swaths appearing in internet searches look like futuristic artistic impressions and 3D renderings, one could assume photos would exist had they actually been commissioned. The smallest I could find in use looked like they might be 60-80' LOA.

    Understanding the sensitivity of the "small water plane" to trim as the COG changes, there must be some maximum ratio of moveable mass in relation to static displacement that would guide a designer. (Considering this more carefully a trimming moment might make more sense to apply to such a ratio should such a concept have any useful application)
     
  7. Ad Hoc
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    Ad Hoc Naval Architect

    There is SSC MARINE ACE by Mitsubishi...that is 11.0m Lwl.

    I've also designed one a similar size just 13.3m Lwl
     
  8. 32ballew
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    32ballew Junior Member

    I think I could stay under 500kg. Think I could stay in the center of the boat except to deploy the motor and land fish. So I'm thinking it could tilt all it want for those brief moments as long as it didn't tip. Is it possible the boat would flip over?
     
  9. Ad Hoc
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    Ad Hoc Naval Architect

    Yes...very much.

    That's why you need to investigate what you really want, properly.
     
  10. 32ballew
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    32ballew Junior Member

    Want a small boat I can fish off of in the wind. Open to all ideas.
     
  11. johnhazel
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    johnhazel Senior Member

  12. 32ballew
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    32ballew Junior Member

  13. messabout
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    messabout Senior Member

    Water in the inside of the boat must be carefully controlled by having it in enclosed sections so that it can not slosh around. Unless contained, loose water can easily cause a capsize.

    If you have two to three foot waves you must have some brisk wind. If you fish standing up, just the aero drag from your body will cause the boat to drift. The best you can do is diminish the drift rate by some kind of practical method.

    A simple box or barge like boat is more practical than a pontoon boat unless the pontoons are very large in diameter. Something like a fat Jon boat could have large leeboards that would slow the drift rate effectively. The boat could even have a leeboard sort of thing mounted to one end of the boat, sideways, so that it would resist drift in the fore or aft direction. Devices of that sort are simple enough and they would be more affective than flooding the boat and far safer.
     
  14. Mr Efficiency
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    Mr Efficiency Senior Member

    If wind drift is the problem, I would go with streaming a drogue, unless it is shallow with snags. It is a not uncommon practice with offshore line fishermen, where conflicting winds and currents sometime create difficulties getting the lines down deep. There are more line-burning beasties out there than in a Montana lake, I would surmise, so it should not get too much in the way of your fly fishing. Pioneering SWATH fishing dinghies sounds like hard work, and unnecessary complication.
     

  15. portacruise
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    portacruise Senior Member

    Seems simpler to build an ergonomic seat for a float tube to relieve your back issues. I did that with a foam topper with cut outs and a good lumbar support for my back issues. I'm not a FF, but how do you control a fly cast in such rough conditions of wind and waves, even if you stand steady on a pier?

    Anyway, here's something that might be useful for swath considerations:

    http://www.rickwill.bigpondhosting.com/V8.htm

    PC

     
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