Design Issues for small, sail/human powered cruising boats

Discussion in 'Boat Design' started by scotdomergue, Jan 6, 2014.

  1. scotdomergue
    Joined: Jan 2009
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    Location: Twisp, WA USA

    scotdomergue Scot

    I continue to think about, pay attention to, and design small sail/human power cruising boats. I've learned a lot and changed some over the last 5 years. I have much greater (though still limited) experience with tri's, and have paid a lot of attention to the smaller boats competing in the R2AK and Water Tribe events and showing up on the web. I continue to find sliding-seat rowing my preferred mode of human power, at least partly due to back problems that make significant periods of both fixed-seat rowing and paddling problematic. At age 72 I find that comfort and stability are a little higher priority - and I continue to be a minimalist and be comfortable with far less stuff and space than most! I also find myself returning to an interest in boats that could, potentially at least, take me almost anywhere, even across oceans.

    I'm currently refining a design at 15.75 feet with 4-foot beam, using Divinycell panel cores and fiberglass/carbon/epoxy skins. I expect I'll build it this summer. Basic boat weight should be 55-70 lbs, perhaps 100 with all sailing and rowing gear and small solar power system for electronics.

    I'll be very interested in any further thoughts on this general subject. Have any of you changed your thinking these past years? Any new ideas? Any new folks interested?
  2. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell "Whatever..."

    Didn't you build a better boat for R2AK?
    As I recall it broke just before the race.
    Was it too light, in the wrong place, and broke?
  3. scotdomergue
    Joined: Jan 2009
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    Location: Twisp, WA USA

    scotdomergue Scot

    Yes, I designed and built Sealark, a 19-foot tri with akas that pivoted to bring the amas inward for rowing. The design and build were rather rushed, trying to be ready for the R2AK. Yes, the vaka-side end pivot points of two of the akas broke. Toward the end of the build I'd had misgiving about these, but in the rush didn't address it. Otherwise the boat worked out fairly well as far as it went.

    From the experience I concluded:

    Tri's are complicated and heavy compared to unballasted mono's of comparable space (not new information, but of greater importance to me after the experience).

    Moving the amas in for rowing wasn't worthwhile. The boat performed well in very light wind and it was easy to move by paddle at 2 knots while fully rigged for sailing, getting up to 3 or 4 knots with just a little help from the sails in a breath of wind. It took significant time and effort to switch between rowing and sailing modes. The swivel akas added complexity and had other disadvantages.

    I need a little wider sleeping platform than the bottom of that vaka hull for long term cruising.

    If I'd fixed her (almost certainly changing to fixed location akas, removable for transport), she still would not have been a boat I wanted. She wouldn't be suitable for long-term, live-aboard cruising and would be too big, heavy and complicated for a boat that wasn't.

    She could have been fairly easily fixed, but I was really burned out from the rushed build and was ready to move on. It would have taken too much time and energy to do the work and then to test her to the point where I'd feel good about selling her at an adequate price. I probably could have modified her to be more suitable for long-term cruising, but I wasn't up for it. Instead I offered her for sale "as is", and , when she didn't sell quickly, sold parts (mast, sails, etc. and later the hulls).

    I enjoy designing and using boats, but am much less enamored of building them. I build because it's how I can afford to create/have the boat I want. If I could find and buy what I want at a price I can afford, or afford to have someone build what I want, I'd be happy to do so. I bought an old San Juan 21 a couple of years ago and enjoyed a few months cruising on her, but, again, she wasn't the boat I want long-term.

    Most of my cruising is likely to be solo. A boat that's what I want solo, and is adequate to occasionally have another person along on shorter, less demanding trips makes sense.

    Sealark was a valuable learning experience, and fun during the couple of weeks of sea trials before she broke.

    I've continued to design some small cruising tri's, but have decided that, for me, currently, the very light, small, 16-foot mono makes more sense.
  4. Squidly-Diddly
    Joined: Sep 2007
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    Location: SF bay

    Squidly-Diddly Senior Member

    "My Marsh Duck is an 18 foot long, 42 inch beam mono-hull with small aft cabin and 107 sqft fully battened sail."

    how about some pics?
  5. scotdomergue
    Joined: Jan 2009
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    Location: Twisp, WA USA

    scotdomergue Scot

    anchored, watmough bay.jpg sailing.jpg

    Attached Files:

  6. Clarkey
    Joined: Aug 2010
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    Location: UK

    Clarkey Senior Member

    This is a topic which really interests me, thanks for all the insight and ideas.

    I have been playing around with a few thoughts for a while now. What I keep coming back to is a small (approx. 13' x 4-5') rowing catamaran that basically just provides a platform for camping on the water. Other ideas creeping in are:

    • A small rig designed to assist rowing upwind, rather than down.
    • Ability to row from sitting or standing position
    • Rig(s) would also be easily reconfigured to provide some shelter both under way and at anchor.
    • Use of a rollable swag tent for accommodation.
    After a few years of career and relocation hell I am now making first cuts in a pile of plywood and hope to be on the water in the spring.
  7. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

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  8. Tiny Turnip
    Joined: Mar 2008
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    Location: Huddersfield, UK

    Tiny Turnip Senior Member

    Here is the assembly and launch of the slightly smaller and definitely simpler re-design of the Solway Dory Osprey, similar to my trimaran earlier in the thread. Lots of neat details, particularly the beam and ama connections, that make the assembly and rigging very quick and easy.

    A few further thoughts relating to my tri.

    The handling on land is very important to me. I would like an easy way of getting the trolley under the hull when landing (while still afloat) and into the boat when setting off. I'm working on an idea for this.

    Most of my sailing, certainly expedition sailing, is with two people, which makes paddling, and lifting and carrying the boat on the shore so much more viable.

    I am continuously attracted by the idea of sleeping on board, and am thinking of a boom tent that goes out to the amas, with tramp/hammock stretched between the beams on each side, for sleeping and sitting with feet in the hull. However, the realities of sleeping in a small boat at anchor, and the associated anchor dragging anxieties and movement in chop, mean I have so far come back to beaching the boat and sleeping in a tent.

    Here's some pictures of camp cruising in my SD trimaran:

    Snufkin round about Mull

  9. Zilver
    Joined: Nov 2007
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    Location: Amterdam the Netherlands

    Zilver Junior Member

    Hello TT, I use a dome tent on my little trimaran the way you describe. Because of the foot(and sleep)well the headroom in the tent is very genereous. Also I can store all my stuff on the trampolines, but underneath the outer tent.
    I always try to get a sheltered place, else the light boat is much to rocky and noisy for sleeping/resting.

    Greetings, Hans

    bajansailor likes this.
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