adding mast/keel through scupper holes of SOT kayak?

Discussion in 'Boat Design' started by Squidly-Diddly, Aug 7, 2017.

  1. Squidly-Diddly
    Joined: Sep 2007
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    Location: SF bay

    Squidly-Diddly Senior Member

    I'm now the proud owner of a well used on one of these. Tarpon 160 https://www.wildernesssystems.com/us/products/tarpon-160

    I also live near a brand new kayak launch ramp, but the area is also VERY windy. Like they got signs on the highway nearby warning motorists about the winds, and some modern windmills nearby.

    So I'm thinking if life gives you lemons make lemonade.

    SO.....

    How about some PVC pipe with appropriate padding collars through the scuppers, and some keel fins underneath? The lower section of pipe could have slits and that would secure the keel fins. Its got 3 sets of scuppers, so how should I shape the fins and which scuppers should it use?

    What sort of mast and sail shape?

    Is using the scuppers just a bad idea all around and only going to give me hard to repair hull damage in the worst spot?....and should I stick to clabber boards and deck mounted sails?

    my boat also comes with TWO big deck mounted fishing rod holders in standard position just aft of seat. Maybe an Arab Dow style sail with an A-frame rear mast?


    PS-judging from the comments, not everyone is as thrilled about the new kayak launch pier as I am. Whoa! Tough crowd. Antioch Marina Announces New Kayak Facilities http://eastcountytoday.net/antioch-marina-announces-new-kayak-facilities/
     
  2. jorgepease
    Joined: Feb 2012
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    jorgepease Senior Member

    Haters! lol, I have the Tarpon 1200, seems to me like it's strong enough to hold a small mast with some stays. Wonder if you would have problems staying upright, mine is a little tippy.
     
  3. Skyak
    Joined: Jul 2012
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    Skyak Senior Member


    SOT kayaks are pretty easy to add sail power to and the strong steady wind in your area makes the job easier. The downside compared to sit-it kayaks is the higher water and wind drag of the SOT make upwind a bit more difficult -while upwind ability is very important in your strong winds. Building a bottom mount keel may be more trouble than it is worth -to do it right I would make a base out of fiberglass using the hull as the mold. Doing it poorly with PVC pipe negates the slight advantage of the bottom mount keel -you would be better off with a good lee board off the side. No matter what you do the bottom keel will increase draft and be susceptible to damage.

    For the mast I recommend aluminum tube or wood. PVC just doesn't have the stiffness and light weight you need. It would be a good idea to get a large diameter thin wall tube and flatten it into an ellipse (seal the ends so it floats). For a sail you want something relatively flat and battened so it won't flog. The reason is that the amount of sail you can carry safely depends on how strong a gust you can survive by dropping the sheet. I think you would be better off making two good battened sails of different size than trying to build an effective reefing system.
     
  4. Squidly-Diddly
    Joined: Sep 2007
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    Squidly-Diddly Senior Member

    I'm thinking of using smallest Windsurfer sail (we got high winds and large group of high speed Windsurfers on W shore of SF bay) and whittle down a cheap standard wooden paddle and ram the paddle's shaft into the Windsurfer mast, then a few braces from just below the sail to the deck of kayak.
     
  5. markstrimaran
    Joined: Dec 2014
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    markstrimaran Senior Member

    OUT RIGGER.

    Up wind or on a broad side run. You will tip. Unless you can stand up and wind surf.

    I used a tent cover as a down wind jib, with the oar as rudder keel.
     
  6. Squidly-Diddly
    Joined: Sep 2007
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    Squidly-Diddly Senior Member

    I'm trying to dream up an easy way to add one or two outriggers that can also stay out of the way of a double-ended paddle, when paddling is called for.
    I'm thinking something that would pivot in total of 6 places so one float would go forward and one aft when collasped against the hull, with pivots on the hull just fore and aft of cockpit. When against the hull they would still provide a bit more stability.
     
  7. sharpii2
    Joined: May 2004
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    sharpii2 Senior Member

    This seems to be a perennial problem in boat design.

    A few years ago, I came up with my own solution (see illustrations below).

    I realized that a double outrigger is nothing more than a small catamaran which pulls it's floating ballast (the vaka or main hull) through the water.

    The system I sketched is a complete catamaran minus the rudder. It straps onto the main hull, and the rudder is added to the stern of the main hull. The long, shallow keels, although less efficient than deeper boards, do not extend below the main hull. Another advantage they have is that they have an effective angle of attack which is very similar to that of the sides of the floats they are attached to. So when the leeward float starts to immerse, its side adds lateral plane.

    This rig would never point like a Laser(r), but I believe it will have adequate windward perfomance.

    The floats can be made of slabs of foam glued a plywood side/keel piece. triyak.png Triyak2.png
     
  8. markstrimaran
    Joined: Dec 2014
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    markstrimaran Senior Member

    20190320_201538.jpg
    Theirs always the Hobie bicycle peddle drive.
     

  9. Squidly-Diddly
    Joined: Sep 2007
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    Squidly-Diddly Senior Member

    good points, I'm now re-thinking the use of center board connected through the mast because I realize what I really want to do is use this in shallow and weedy waters, and it would be 2/3 paddler 1/3 sailor. So shallow keels on the outriggers sounds reasonable. Might go with 6" dia pool noodles, up-turned at ends, with PVC pipe core, and 1/8" plywood keel embedded into the pipe and through the noodle.
     
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