Tiny boat for canal cruising - any suggestions?

Discussion in 'Boat Design' started by alexlebrit, Aug 20, 2008.

  1. alexlebrit
    Joined: Aug 2006
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    alexlebrit Senior Member

    David, I see where you're coming from with te bow wheel, although personally I'd be happy without it, the banks aren't that smooth anyway so I'd need a full size bike wheel n the front too just to cope with the bumps, in fact I'd be better off with a "tadpole" design with the two wheels towards the bow and a single tail wheel.

    As for bike axkes, there's plenty which will cope with 200lbs plus, the things to look for is the 20mm axles used by some mountain bikes. I've got a tadlpole trike already and it's fine with single sided support.

    And some more of my own thoughts, I've pretty much decided that I'm not going to paddle/row the thing apart from manoeuvring maybe. I'm now the proud owner of two 2.5hp outboards both of which I've got working, so motor it'll be, it's getting too late in an already wet summer to be rowing about in the rain (that's just me). So instead I'm aiming for a flat/slight V-bottomed boat with a sampan style canopy over it which I can always sit under if I'm motoring in the rain.

    2 boats designs leap out at me for this, either a stetched (both directions) ScoutCanu as seen above or one of the Expedition Mouse boats. Both would be 14 feet long which keeps me under the limits here. So it's down to flat or V, and slightly down to which one would use more ply.

    Unless of course anyone can suggest a better idea.
     
  2. kengrome
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    kengrome Senior Member

    Well, efficiency won't matter now that you've decided to use an engine, so I would go with a flat bottom because they are easier to build and easier to move around in.
     
  3. alexlebrit
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    alexlebrit Senior Member

    Foam sandwich

    Right ok, here goes, deep breath and wait for the purists to scream.

    I've been thinking about this, and what are my main requirements?
    1. Float
    2. Keep my backside out of the water
    3. Keep the weather of me.
    So I've been looking at foam, which I know is a dangerous thing, but it got me thinking. IF, I made a ply/foam/ply, I could use but the thinest ply externally to protect against denting and abrasion and have a very lightweight boat.

    Ahh, scream the purists, foam has no structural intergrity, the boat will fall apart and you'll drown and die and the fish will eat you up. BUT, lets think about this for a second. The boat is:
    1. Very shallow draft
    2. In shallow water
    3. In calm water
    4. Pretty much single use
    So, given that I can get foam up to 50mm in depth, and I can of course bond it together, and that the total weight of the boat and load is quite light, I can easily see that what I can basically have is something akin to a Sit-On-Top kayak or even a raft. This meets with the first two requirements of flotation and a dry bum.

    Now the rest of the hull becomes much more about keeping the weather off, If I lay on a raft the wind and rain can come at me from all sides as well as from above, what I want are "walls". And these could be almost anything, a fabric skin, a very thin ply, or foam, or a combination.

    I know it's not pure, and I know that I wouldn't like to be out at sea, or even in a moderate chop on it, but for this precise use, and given that weight is a huge issue with all these locks, I think I might experiment a bit.

    Then again - see below.
     
  4. alexlebrit
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    alexlebrit Senior Member

    Or a big coracle.

    Sticky my next out a bit further I found Hannu's coracle page HERE. And this set me thinking a bit.

    [​IMG]

    OK so as it sits there it doesn't really suit me at all, it's too small and it'll spin me round and round like a top. BUT it is light. So I'm now wondering about using the same basic techiniques to build something similar but bigger and particularly something longer and a bit more Sussex Trug like in shape. It'd be light, it'd keep my bottom dry and it'd hopefully go in the right direction.

    How you sling an outboard on it though.
     
  5. Tad
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    Tad Boat Designer

  6. alexlebrit
    Joined: Aug 2006
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    Location: France - Bourbriac

    alexlebrit Senior Member

    Both the Escargot (very appropriate for where I live) and the Jonboaty thing are great boats and I'd love to use either if the canal had a fully working lock system BUT it doesn't :(

    I was looking through last year's journal when I cycled the length of the canal towpath and had noted down the closed locks. All in all there's 37 closed locks, including a flight of three in quick succession, and a flight of 12 in 1.6kms. Not to mention having to portage round this

    [​IMG]

    in the middle.
     
  7. diwebb
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    diwebb Senior Member

    Hi alexlebrit,
    if you are looking at the coracle type of construction, skin on frame, then you should look at Platt Montfords geodesicaerolite designs. You can see them on his website at gaboats.com
    the 14 foot whitehall might suit you.
    David
     
  8. masalai
    Joined: Oct 2007
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    masalai masalai

    Could I suggest a tiny boat already built, that is designed for canal cruising?
     
  9. alexlebrit
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    alexlebrit Senior Member

    You could, but I can't think of one, the closest would be a ready-made kayak nothing else comes close to being light enough to portage round the closed locks - which is probably the biggest design challenge in this. And also I like the building challenge too.

    I love the geodesic boats and it goes well with the geodesic dome I've currently got sitting in my garden. I'll be looking at them closely to see how they could be made sleepable-inable.
     
  10. Meanz Beanz
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    Meanz Beanz Boom Doom Gloom Boom

    Mebe a motor canoe (link)... mebe polycore and glass/epoxy, light and stiff. The 12 to 16 ft cedar strip boat could be done very lightly.
     
  11. diwebb
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    diwebb Senior Member

    Hi Alex,
    if the object is to cruise the canal as economically as possible then I would suggest the simple plywood skiff I did the sketch of earlier in this thread. It will be very quick and easy to build, and does everything you say you want to do. more exotic, or untried methods will cause more expense and more trouble in the long run. Stick to the simple tried and true plywood skiff and you should have an enjoyable and trouble free canal cruise.
    Good luck with the project.
    David.
     
  12. Meanz Beanz
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    Meanz Beanz Boom Doom Gloom Boom

    Untried.... LOL

    I suggest you stick to known designers :p
     
  13. kayakn
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    kayakn Junior Member



    I like this idea. you don't want to be uncomfortable you're whole trip and this boat looks like it would be comfy and just the right size
     
  14. lewisboats
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    lewisboats Obsessed Member

    Packin that over his shoulder might be a bit of a pain ;)

    Steve
     

  15. ancient kayaker
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    ancient kayaker aka Terry Haines

    With motors efficiency is not relevant; weight and bouyancy are main issues, durability would be nice but if you can swim to the bank and don't mind abandoning your stuff you can take a bus home so it's secondary. Your problem is, there's not much existing designs out there that are suitable.

    I think the foam/ply sandwich is a good idea; with an adequate sized boat you'd have about 1/4 tonne of bouyancy and a box structure around the foam and adequate gunnels should create stiffness. Don't stint on the ply although marine is expensive, depends what's available in your area. A somewhat narrow boat would be lighter and easier to portage especially if you have to deal with gates and such. You could add inflatable sponsons for stability.

    One caveat; on your planned trip will you encounter motor craft driven by the intellectually underprivileged? Or large lakes surrounded by cottages and cottagers trying to catch the stores before they close? If so pay attention to durability and stability.
     
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