Duck Punt - with a twist

Discussion in 'Boat Design' started by Jeremy Harris, Mar 29, 2012.

  1. troy2000
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    troy2000 Senior Member

    And tritto?!? Or do we go by powers and make the multiple of ditto quatro?:p

    Whatever, good luck. A very nice little project.
     
  2. Jeremy Harris
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    Jeremy Harris Senior Member

    Thanks the kind wishes - they worked! Although "Quackers" the Duck Punt wasn't the fastest boat, we won the prize for "innovation" (somewhat paradoxical as the boat design is around 200 years old), so I'm now the proud owner of a new Makita tool kit.

    Boat speed was around 6 1/2 kts I think, as I only narrowly lost (by about a boat length or so) to a boat that the owner (Dennis A on here) knows does 7 kts. According to onlookers, even though I was sitting well forward of amidships the front 1/4 of the hull was up out of the water, not surprising as it was going about 50% faster than hull speed. Manoeuvrability was pretty good, it turned at speed in less than a boat length, handy when rounding the marks. Power input was pretty high though, as the drill battery pack (an 18V, 3Ah lithium pack) was too hot to touch after the race.

    I'm certain we'll see planing boats next year, as a couple of us came pretty close to it this year. The event isn't really made by the speed machines, though, it's the variety of fairly typically British ideas that find their way into the entries than make it such fun. Here are some photos I took (so none of "Quackers" I'm afraid) that give a flavour of the entries this year.

    The paddle boat, Ayrspeed, was fully amphibious and drove down the slip straight into the water. He competed last year, with "only" four cordless drills driving the paddles, this year he'd added two more drills driving auxiliary propellers.

    Long tail drives were popular, with several boats sporting model aircraft propellers on the end of long shafts.

    The air boat drive was pretty effective, I suspect that if we'd been pitched against each other in the heats we'd have been pretty evenly matched, as when we ran a short distance alongside each other after the race (albeit when I had a nearly flat battery) we seemed to be pretty close in speed.

    The most entertaining entry by far was the gentleman who built "Something Fishy", a flapping fin propelled shark, with the pilot lying inside the submerged hull. Getting in was like something from a James Bond film, as the bow section opened up and the gentleman swam in feet first, whilst his patient wife stood knee deep in water holding it for him. It wasn't fast, but did make it around the course, with the pilot steering via a mirror mounted on the "conning tower). Only in Britain would you see this level of eccentricity, I suspect.

    The winner was "Velociraptor", driven by a V4 array of four cordless drills driving a single shaft and model aircraft propeller via a lot of bevel gears. It was, like "Quackers", running at well over hull speed and clearly climbing her own bow wave. I suspect that with a flatter section aft she might have got up on the plane, or at least closer to it.
     

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  3. troy2000
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    troy2000 Senior Member

    Great pictures; thanks for posting them. Sounds like a very successful event.
     
  4. Doug Lord
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    Doug Lord Flight Ready

    Well, Jeremy-I think you won based on the inspiration of so many on this forum. Great food for thought -thanks!
     
  5. Jeremy Harris
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    Jeremy Harris Senior Member

    I'm certain you're right, Doug, and am thankful for all the helpful advice gleaned from here over the years. I'm pretty sure that at least one other competitor in this event has similarly relied on advice and help from here, too.
     
  6. heavyweather
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    heavyweather Junior Member

    You can find opinions on almost any foam material on swaylocks.
    XPS as you pointed out already is destroyed by sunlight and the other issue with it is gasing out. The solution the surfboard industry found is using valves in the boards. Otherwise they will start to delaminate some day.
    Now that the thread is already two years old did you notice any delamination? Maybe you can not compare a boat to a surfboard that is exposed to the sun quite often and sitting around on the beach for days.
     
  7. Jeremy Harris
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    Jeremy Harris Senior Member

    No sign of delamination at all so far, and it's sat outside, upside down and tied up under a transparent plastic roofed car port most of the time, so gets a fair bit of sun.

    Bert Rutan has been making aircraft using the exact same method, with XPS foam, for around 20 or 30 years now, and I've not heard of any problems with his Eze series, of which there must be a few hundred that have been home built and are flying around the world by now. I really used much the same technique as Rutan came up with all those years ago, lightly sand the XPS, fill the top surface with a wet mix with some micro to key into the XPS and squeegee it off so there's virtually nothing left on the surface. Let that partially cure, then lay on the cloth, apply epoxy and squeegee it to get all the excess out. I used peel ply to get the glass/resin ratio as high as I could, but the cold weather when I was doing it meant I didn't get as good a job as I should have done, and the hull ended up a kg or two heavier than I wanted.

    I have a friend with a custom surfboard board business down in Cornwall and he either uses pre-blown EPS blanks with epoxy/glass for the cheaper boards, or hand shaped PU foam blanks and vinyl ester/glass for the custom jobs (usually with fancy artwork). I've not seen him use XPS, but next time I'm down there I'll ask him if he's used it and what his experiences with it were.
     
  8. Yobarnacle
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    Yobarnacle Senior Member holding true course

    did you get the chance to try it with a Flettner rotor?
     
  9. Jeremy Harris
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    Jeremy Harris Senior Member

    No, not yet, I've been flat out building us a new home for the past year or so, with no time for any boat projects, I'm afraid. I have built a nice, big, well-insulated workshop into our new home, though, so I anticipate that more boaty stuff will be built as soon as we've moved in and sorted out the landscaping!
     
  10. Yobarnacle
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    Yobarnacle Senior Member holding true course

  11. messabout
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    messabout Senior Member

    Jeremy; You have given credit to forum members for part of your boaty enlightenment. That acknowledgement must work both ways. You too, have contributed some thoroughly useful information over time. Thank you for that.
     

  12. John Forney
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    John Forney New Member

    Jeremy, what would you do differently if you were to set up this boat for an Optimist sail rig? Would you add any fiberglass on the bottom?

    I'm thinking about making a boat like this, and putting two layers of 4 oz. cloth on the bottom.
     
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