this 19' Transalt based hull catboat looks like it might be close to my

Discussion in 'Boat Design' started by Squidly-Diddly, Sep 9, 2012.

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

    idea for hybrid high performance sailing dingy and speed boat.

    I didn't notice any rave reviews by the builder of how good it sails, maybe I'll try to get in touch and ask.

    But how would a hull like this do with 25hp or more outboard, with either heavy or light load and in smooth or not so smooth water?

    Sorry about the big cut&paste.

    The boat is said to be 19' long by 7' wide at the stern and "arrowhead shaped".

    For my part, I'm trying to come up with a "universal sport and work boat", able to either sail fast for fun and economy or motor at low planing speeds with an outboard.

    My original thread on the subject.......

    Here is the original link from WoodenBoat about various non-pro designed and built boats....

    1. [​IMG]

      It's much easier cutting and pasting ply than pixels. I might have the hang of it.
      Intent was an easy sailing lightweight sailboat. Trailer behind a Prius. Minimal boom intrusion. So the arrowhead shape of the mini Transats was used. That
      provided the extreme (7') beam at the stern. Thus no centerboard weight is needed, it's all human ballast. The catboat rig provides enough square feet--104
      square feet on the main--and the boom stays well forward'. Haiku is 19 feet long, with the trailer and all gear aboard she weighs 420 lbs. ​

      [​IMG] Reply With Quote

    2. [​IMG] I started with a doorskin model of what I thought I wanted, and scaled the hull bottom panels to two scarrfed lengths of 19' ​
      [​IMG] Two layers of 1/4" okume make up the bottom panel of the hull. Cut to shape and flipped for symmetry a couple times, I slathered the epoxy on both surfaces ​

      [​IMG] The trailer is blocked in at least eight places, there's a center cut at the bow of the bottom panels to provide some greater rise at the bow. Overall I got about 4" of rocker and about 3" of bend at the stern. Drywall screws minimized voids where there were no posts pinning the panels down. When I cut out the centerboard slot both panels were joined. As for the rest, we'll never know ​

      [​IMG] If you recall the scale model, it suffered gaposis. More careful measurment of battens placed where my eye said was right helped to produce the angled bottom panels. Scaling only goes so far, and I prefer to work with the reality of the full size. Working with 1/4 okoume is done readily by one person, and temporary braces to hold things in place lets you eyeball and contemplate.... Yes, other than the model I had no plans. I DID have the finished shape in mind.

    3. [​IMG] And so more panels went into place, and removed to sand edges, etc, or to scribe the three dimension edge of a bottom to an angle to a side panel... The stitch and glue construction got three bands of glass on the outside, but I chose shaped cedar clamps bedded in thickened epoxy on the inside. ​

      [​IMG] Paint for the bottom, and that's when I cut the centerboard trunk opening. Pics don't show the three mast positions I was ready to use to get the right weather helm. Easier to move the mast.... It turns out the eyeball engineering was OK and I have mild weather helm at the favored foremost mast position ​

      [​IMG] The green motif started with Ikea shelf brackets that support the upper pin of the rudder. We're fortunate to have the best used sailing supply store on the entire east coast, Sailors Exchange, here in StAugstine. The formed cherry seat perimeters came from there, and that's how I have quarter stern seats and half round midships seats. It was around in here, putting in the coaming deck, that I lost a sweet sheer and came up with the prosaic one. Until the decking went on, I thought all was pretty yar. ​

      [​IMG] I'm a sucker for the dreadnought bow. Yes there's some bondo and glass in there. In some of the fotos you might see a hollowed bow I was able to torture from that large area of side panel. ​

      [​IMG] There are small compartment in the box member that creates the decking and the coaming. I need to enlarge those and probably use plexiglass so I can see where all the oddsnends are. I carry spare bearings for the Suzuki motorcycle wheels, well greased, and the rod to change them out. The chainplates are super strength line that is knotted off underneath the sheerclamp. The mast thwart is substantial SYPine, and the mast shrouds tug down on a mast collar at deck level, so I'm not trying to push the base of the mast through the bottom. The mast step locates the base of the mast forenaft and side to side, but bears no weight. ​

      [​IMG] Another stern shot. The bottom panels provide a swim platform with about 5" and I can watch that area underway and know when to move forward and leave a smooth wake. The first picture, and only one under sail, shows lowers at half mast and uppers at the top. My stacked sailboard mast moved into all kinds of shapes. No good. I followed sailors' good advice and lowered both. Still too much mast bend. Haiku has impressed some fellow racers: as a catboat she is fun and lively with 104 ft2 of sail. The combination of low weight and flatish bottom and the given sail are good. I found a kickup rudder at Sailors Exchange. It came from a Walker Bay 10. It works great. Build time was 5 months. She's clearly intended for sheltered waters. I have Dow foam in the bow and behind the coamings. Haiku is eminently reefable: The mainsheet ends at the boom with a one-squeeze clamp. To reef, slack the clamp, grab the boom, loosen a foot of halyard from the jamcleat, roll the surplus sail onto the boom, and reset the clamp. More fotos when the heat lets up ​

      Last edited by blisspacket; 07-28-2011 at 06:11 AM. ​

      Join DateNov 2001LocationStAugustine, FL. USAPosts112 [​IMG] This is one of two aluminum fittings that I use on Haiku to eliminate drilling in the sailboard mast. Epoxy a glass collar at the appropriate height, slide this on as the epoxy cures just to minimize point contact. I've tried light dynema, which stretches time and again. Then wire, which is too heavy. Back to heavier amsteel blue, which is better but still there's creep. Once I forgot to stitch the brummel splice. Only once.... Keeping it light means one person can heft the 23' mast into place without incident.

      if i had built something like that, I'd have added a cabin, and added a larger rig. ​

      [​IMG] Re: Non-professionals who have designed and built their own small boats

      One fall on Martha's Vineyard I built a 15' skiff for scalloping in one day. Painted it the next. Put a 25 Evinrude on it. The "design" and building were more or less simultaneous. It was a really fine skiff. Stable, dry, fast. Pretty decent looking if I do say so myself. 2x4s frames, sheet rock screws, 3/8" CDX plywood and liquid nails to keep the water out. If I find a photo of it at speed, I'll scan it and post it. Scalloped out of it for two seasons in often fairly awful November/December weather crossing Edgartown Harbor to Cape Pogue pond in a two-foot chop/snow.

      Many years earlier I felt inspired to build a 12' rowing dory in the basement. Took me about two days. It was pretty tender, but rowed nicely. It was almost exactly like a Bolger Gull, only shorter. I think I left it on a
  2. blisspacket
    Joined: Jun 2005
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    Location: st augustine

    blisspacket Junior Member

    re minitransat copies

    I'm the designer builder of Haiku. Have since changed to sloop rig with 24' of luff on the main. 17' luff on the jib, 110 percent. I wish I could say it's a speedtrip, but so far it's not. My preference for lightair sailing leads me to think there's too much wetted surface to get max displacement speed. I haven't had lightweight crew aboard or the nerve to throw up an asymetrical on my own. Sail area is still relatively modest: the slightly longer mast is a stack of carbonfiber sailboard masts and readily assembled/rigged by one person.

    Small features worth copying: the 5" lip from the hull panel that extends beyond the transom. Big boats call this a stern boarding platform. It's eminently sensible in a small open boat when your launching from a beach ora trailer.

    Perimeter steering: in addition to the tiller, a yoke that ties on to the tiller and is actuated anywhere on the boat. Carbo blocks in four corners of the interior and some lo-stretch line are the makings. The singlehander can be adjusting centerboard or cunningham or whatever, and not have to scramble or mess with a superlong hiking stick.

    The dreadnought bow comes about readily when, instead of tapering the side panel of hull, you widen it at the bow. Good plywood tortures readily enough, and Haiku has a spoon hollow in her bow. The bottom panels are tortured and a narrow v was cut so she does have rocker. And perhaps that same long waterline that one seeks for a displacement hull is what slows her down by adding to the wetted surface.
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  3. Squidly-Diddly
    Joined: Sep 2007
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    Location: SF bay

    Squidly-Diddly Senior Member

    thx for reply, my guess is those Transalts are meant for

    white knuckle balls out sailing in strong wind, and unless planning wont do as well as traditional hulls.

    Have you considered putting an outboard on it?

    Another hull design I'd consider would be MacGregor with less freeboard.

    Its proven motorsailer semi displacement. I'd hope Mr MacGregor wouldn't be too upset if little old me makes just one of something very close to his hull, at least the lower in the water part.

    I figure cutting the hull about mid way from keel to gunnel would be about right for the sort of boat I'm thinking of.

    Maybe I could find one that got top destroyed.

  4. mydauphin
    Joined: Apr 2007
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    Location: Florida

    mydauphin Senior Member

    Darn I was thinking the same thing, just cut the top half off with my circular saw, and chain saw in some places.
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