Design Issues for small, sail/human powered cruising boats

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

  1. scotdomergue
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    scotdomergue Scot

    Yes, certainly challenging. That's part of the fun, I think.

    Yes, your last doodle has lots of similarities both to my Duck and current design . . .

    Remember that Hans Lindemann crossed the Atlantic in a Klepper Arius II, and Fredrick Fenger sailed the Caribbean in his 17-foot open sailing canoe. And a corked bottle has no problem riding any size waves.

    The smaller the vessel and lighter the weight, the less the forces involved, and therefore the lighter can be the construction and weight. Given modern materials, I think it is quite possible! My current design is my best effort at meeting all my various desires - and is not yet set in epoxy . . .
     
  2. scotdomergue
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    scotdomergue Scot

    If you haven't seen them, check out Sven Yrvind and his boats and voyages, and Aleksandr Doba and his 3 times crossing the Atlantic in a 23-foot, 1500 pound kayak (virtually unmanageable in serious weather due to lack of power of kayak paddle and size/weight of boat).

    To me, weight seems more problem than beneficial.
     
  3. peterAustralia
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    peterAustralia Senior Member

    I don't know. Sven,,, ahhh. He is going backwards going from making good boats to silly ones.

    44 inch beam on a marsh duck style boat . Hmm, ok

    When you get ocean crossable, then your carrying 400kg , 900 pounds. In that scenario a flat bottom 100 pound boat, with narrow beam, no keel, zero deadrise, all sorts of problems.

    My prediction is you would get rolled 1000 times
     
  4. bajansailor
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    bajansailor Marine Surveyor

    My friend Stein set out to row from New York to England 5 years ago - at the age of 70. He had already completed two previous transatlantic rowing expeditions, but in much lower latitudes, and he was much younger (the first one was the Woodvale race from the Canaries to Barbados in 1997 or thereabouts).
    He had a Blog about his North Atlantic trip on Facebook - Stein Hoff - Atlantic Row 2016 https://www.facebook.com/soloatlanticrow2016

    And after about 80 days at sea he was about 500 miles from Cornwall, and he got caught up in a storm.
    The only thing he could do was to deploy his drogue from the bow and shut himself inside the little aft cabin- but when the drogue rope broke he was repeatedly rolled by the waves. It must have been like being tumbled in a huge washing machine.

    He survived thankfully, but all of his oars were broken, and he had no choice but to activate his EPIRB. A huge (at least 200,000 tons) bulk carrier responded to his distress signal, and managed to manoeuvre alongside him in huge seas to take him off the boat. They were not able to rescue the boat as well.
    Stein ended up back in New York, as this was the vessel's destination.
    And as for his rowing boat - she was found by a beach comber a few months later, washed up on a shingle beach in the far north of Norway.

    Scott, for the amount of money that this boat is going to cost you to design / build, you could probably buy a very nice little ocean going yacht that will be much safer and more seaworthy, and much more comfortable.
     
  5. Milehog
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    Milehog Clever Quip

    Back to the needle bow. It is not going to contribute to the bow wave and hull speed as much as you think.
    Good luck.
     
  6. scotdomergue
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    scotdomergue Scot

    Stimulated by this discussion I did a more balanced fore-aft and rounded lines design last night. It's a little heavier and slower rowing and sailing in very light winds, but not as much as I expected from previous related design exercises. She would be more difficult to build. Since the beam is carried forward, the cabin would be a little more roomy (even though it is also farther forward). As has been argued above, I think she's be more seaworthy. I've only begun weight balance and trim analysis, but my first iteration of that looks do-able. I'm leaning toward this design now.

    I would not need 400 kg of load! Designed gross displacement for this version is 370 to 770 lbs . (though she could probably handle more). That's up to 150 lbs of boat (including all sailing and rowing gear and small solar power system for electronics), my 170 lbs, and from 50 to 450 lbs. of gear and supplies. I expect I could safely make ocean passages with between 260 and 400 lbs. of gear and supplies. And yes, modern electronics do provide an extra margin of safety if worse comes to worst. With good efficient sailing and rowing performance, I would be significantly faster than ocean rowing boats.
     

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  7. scotdomergue
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    scotdomergue Scot

    PS: Yes, I could certainly buy an older fiberglass sailboat and prepare it for ocean crossing for the $ I'll put into this project. But it would not do what I want it to do. I had an old San Juan 21 for a while, and set it up for sliding seat rowing as well as sailing and cruising. It was a pig to row, NOT fun and slow for rowing, and frankly less comfortable for solo cruising even with much more room and load carrying capacity. I'm much more interested in my current approach.
     
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  8. bajansailor
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    bajansailor Marine Surveyor

    Are you confident that you will be able to out-run / sail away from a storm if you encounter one out in the ocean?
     
  9. scotdomergue
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    scotdomergue Scot

    No. I'll certainly be able to do that better than most ocean rowing boats, but would always be prepared to sit it out on sea anchor from the bow or drogue from the stern, depending on conditions.
     
  10. Milehog
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    Milehog Clever Quip

    Keep it coming. I suspect this version will have somewhat more predictable motion and therefore be kinder to the crew.
     
  11. CT249
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    CT249 Senior Member

    Nice idea and shape, but 100lb including all gear at 20 x 4 ft? That's lighter than the hull weight alone of an International Canoe (17 x 3' approx); dramatically lighter than a carbon/boron/Nomex 18 Foot Skiff (18 x 5', approx); about 50% lighter than the all-carbon A Class catamarans (18' x 8'approx). Even a 13' Raceboard windsurfer comes in at around 50lb for a vastly smaller craft with no rowing gear.

    Can you really build a cruising boat that is probably THE world's lightest sailboat for its size? Are the people who are charging $50,000 for a 70lb 11ft foiling Moth really building them far too heavy?
     
  12. peterAustralia
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    peterAustralia Senior Member

    The new set of lines look nicer. As to weights, in Oz we use metric. I can't see hull weight under 100kg, you may have more skill experience than me (two plywood rowing boats). Just 100kg would be my starting minimum. As to weights, say 2 litres water for 100 days , that is 200kg. Then add food, gear, rig, oars, rope, all that is easily 150kg. Then add crew, you are approaching 550kg.
     
  13. scotdomergue
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    scotdomergue Scot

    She's 19'10 inches long, 44-inch beam.

    The weights are calculated, currently 69 lbs. for the boat itself (not including foils, sailing and rowing rigs). This includes all bulkheads, interior partitions, scantlings, etc. It's based on Divinycell cores (3/8" for bottom, transom, side decks and cockpit floor, 1/4" for everything else), 10 oz fiberglass/epoxy for outside of bottom and bilge panels, 6 oz carbon fiber/epoxy for everything else (insides of bottom/bilges, both sides of everything else), a little wood trim is budgeted at 2 lbs. The calculated weights of all added together are multiplied by 1.1, adding 10 percent to reach 68.98 lbs.

    Sliding seat rowing gear (9'3" carbon fiber oars, sliding seat on platform/tracks, oarlocks), just over 10 lbs. - these are the actual measured weights; same gear I used with the Marsh Duck. Oarlock outriggers are included in the boat weight.

    Sail rig is also measured weights of spars and sails used on the Marsh Duck, modified for the current design plus calculated weights for new foils, controls, etc. Just over 22 lbs.

    Total 101.5 lbs.

    I think this is realistic, and I expect she'll actually weigh a few lbs. more, but still far under 100 kg. As noted previously I expect a total of 125 to 150 lbs. including all noted above and a small solar power system.

    I imagine carrying water for 30 days plus a hand-pump desalinator and a backup, with which I would maintain at least a 15 or 20 day supply at all times.

    All the other gear and supplies? Long lists with measured or specified weights come to 55 lbs. for a couple of nights of local cruising, 140 lbs. for light cruising in my local waters (the Salish Sea), 260 lbs. for really extended cruising, and up to 450 or 500 lbs. if needed. I expect that ocean passages would usually involve 300 to 400 lbs. of gear and supplies.

    I weight 170 lbs.

    I think this is all realistic. AND, this is an experimental design that is not yet set in epoxy. I will consult with those more knowledgeable and experienced than myself on some particulars before starting the build. Have done so in the past, and some of the particulars are based on information received (including core thickness, skins, and the 10% for as built vs. calculated weights).

    Once built, I expect to use her, first on small local lakes, including capsize and self-righting testing. I'll then cruising the Salish Sea (all of which I've done on my Marsh Duck) before going farther afield (inland passage to Alaska? Pacific coast south to California and beyond?). I may or may not ever want to cross an ocean, but if/when, I intend to be ready to do it in reasonable safety.
     
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  14. kerosene
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    kerosene Senior Member

    Dropping the extra lip is definitely better.
    I am sure you know rowcruiser by Angusrowing (probably mentioned earlier). There is also sailing rigged version with outriggers.
     

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  15. peterAustralia
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    peterAustralia Senior Member

    The Angus rowcruiser and the design in this thread are very similar in overall dimensions. Who on earth would row or sail an ocean in that thing?

    For coastal voyaging looks great, but sailing or rowing for weeks in ocean swell, no thanks.

    Normally sailing boats are a bit wider than rowing boats

    Almost every ocean rower out there is a good 5ft in beam.

    Your on your own, good luck
     
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