How about making a double-ended longboat from 2 aluminum Vee boats?

Discussion in 'Boat Design' started by Squidly-Diddly, Oct 9, 2009.

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

    How about making a double-ended longboat from 2 aluminum Vee boats?
    There was some interest a little while ago about a "Pirate Tour Boat".

    I'm thinking of a durable, cheap, stable and safe "Viking Tour Boat" or "Big Canoe" made out of two typical aluminum utility boats connected at the transoms somehow.

    The idea would be to breath ‘new life’ into some resort operators existing fleet of matching aluminum rental fishing boats. I’ve seen these boats stacked-up and mostly unused at several lakes.

    The Aluminum LongBoat would be used for things like groups of kids and adults who might not be quite up to using real canoes.

    They could also be used as row boats. While they wouldn’t be “fast row boats” their length should make them row a lot better than the individual boats they are made from, and their width should make using a pair of oars, or single ‘sculls’ work OK. They should be able to seat at least 4 rows of rowers, but more likely 6 rows. The idea would be to introduce long boat rowing to newbies at a realistic cost, and without giving a second thought to damaging any fragile shells.

    I can’t imagine many resort operators investing in a purpose built mega-canoe or long boat. Too much specialization and un-recoupable investment, not to mention massive time lag, transportation and storage issues, visions of horrific repair bills, and above all safety certifications required to lend out boats to the public. I’m hoping that all the American factory built safety should stay intact if the boats are simply joined together.

    For non-human powered models a bracket for a small gas or electric outboard could be riveted to the side of what was the bow(now stern) similar to the off-set rudders seen an ancient vessels.


    SO…..how to connect the two boats in a safe manner, that shouldn’t de-value the boats or otherwise be a ‘point of no return’, and make all effort to allow the users to ‘suspend disbelief’ and enjoy the illusion they are in a traditional double ended long boat of sorts?

    Most aluminum boats have modestly angled transoms and in this application that gap/wedge could be “wet” without much effect.

    Most of the boats also have at least a 1” keel extrusion, and often other longitudal rib extrusions that could be drilled into without poking any holes in the boats.

    I’m thinking a single piece of aluminum sheet, over-lapping about 3” onto the hulls and secured somehow to the gunwales and keel extrusions, and caulked along the seams, then paint the whole boat.

    To return the boats to their original use there would just be some easily accessible caulking to remove.




    PS-some aluminum boats began to narrow towards the stern, and some go 'straight back' to the stern. "straight back" would look OK, others would look funny and 'wasp-waisted'.
     
  2. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Since the transom is rarely going to be perpendicular to the LWL, you'll need some sort of adapter. A piece of foam, thick enough to absorb the rake of both transom, but little else, some big *** "C" clamps and go slow. Wasp waisted would be fine at displacement speeds.
     
  3. narwhal
    Joined: Aug 2009
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    narwhal Junior Member

    You might think about extending that 'wedge' connector enough to put an access hatch on the top, and use it for auxiliary flotation or dry storage. Perhaps built out of doorskin ply wrapped around thick plywood bulkheads which in turn could be through-bolted to both transoms and covered with fiberglass, then painted to match the original hulls more or less. If lined with foam, it could be used as a cooler!
     
  4. Squidly-Diddly
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    Squidly-Diddly Senior Member

    I'm aware of the transome rake which is why I mentioned

    using a single sheet of aluminum.

    I forgot to say the sheet would need to be cut from ZERO(plus 3" overlaps on each side) to 2X the transom rake at the keel. Thus the sheet would look ROUGHLY like 2 "V"s or "<>", except much skinnier.

    I would expect some sort of simple mechanical connection at both stern gunwales and the keel extrusion, like a 1'x1"x1/4" metal bar with some screws into the boat. That should give "3 points".

    Those would probably be installed after the joining sheet was bent around the two sterns, and glued with marine caulking. If installing and gluing a single '<>' was a problem trapezoids could be individually glued after the 3 point bars were installed. I wouldn't much care if the gap between the transomes was dry or filled to water line.


    What I am a little worried about is stress on the keel attachments. Keel extrusions were never never meant to take loads of two loaded boats flexing with waves or passengers moving around. Maybe a connecting bar alongside the keel would need to extend a couple feet in either direction to spread the force on to more of the boat/keel connection which is usually riveted. I don't want the connecting bar ripping out the keel and probably ripping a hole in the boat in the process.

    I'd also use premium caulking to spread load of the two boats trying to flex which is why the 3" overlaps(and light sanding of surfaces prior to the gluing.


    Another variation would be HINGES at the top of the transomes, but that would look funny with a gap lower down.
     

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

    narwhale-Yep, I thought of that or extending enough for

    a "mid boat" out board, but then that is getting into all sort of work(plus the outboard couldn't kickup if run aground.

    I'm trying to devise something using only the simplest standard materials that don't take up any storage space. 3 metal bars, a few flat sheets of aluminum(less than 2' in any direction) and a couple tubes of caulking.

    I think the two boats would be plenty storage and otherwise capable(American factory metal and built in flotation).

    The main problem is coming up with something that some resort operator would "go for" which means it needs to put money in his pocket from day-one at no risk or additional effort to him.

    I figure this concept would go from most common 2x 12' rental fishing boats as a very large 24' canoe to 2x 16' for a 36' long "Viking Ship".

    Could also be a Mediterranean 'galley'. Multicultural faux traditional boating. Perfect for tourist picnic on the lake market. Long boats would also be good for overnight camping on the water. Just throw a sheet of plywood down on the built in benches on either or both halves.
     
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