Thread: strengthening the bottom of a mirror dinghy

I would suggest the following,without seeing the boat:

1 sand the hull ,bottom & sides coat with EPOXY RESIN
2 1 layer of 50mm tape on chines & keel & epoxy
3 add an exterior under floor stringer each side of the keel ( if required and glass with tape)
4 followed by a layer of light 200GRM cloth & epoxy over entire hull.
5 Fair and paint hull.

As for the motor (electric) mount on the transom, and the battery midships, or your leads will be come too long and loss of voltage will affect performance.

Also what type of battery are you going to use??? , I would suggest an AGM (absorbed glass mat) as this will give much better durability than a deep cycle marine battery for the application,.

I have seen a 1 man canoe get 4hrs from a 100amp agm battery with a 44lb thrust motor.

I would talk to a reputable supplier as to the motor and battery before buying.

Jeff

Great advice, thanks Jeff.

I just have a couple of follow up questions:

1 sand the hull ,bottom & sides coat with EPOXY RESIN
-any particular type or brand?

2 1 layer of 50mm tape on chines & keel & epoxy
-is this fibreglass tape? Any particular weight or type?

3 add an exterior under floor stringer each side of the keel ( if required and glass with tape)
So on the outside of the hull? I was thinking of adding extra floor battens to the inside, but I'm open to ideas. What I was planning was actually to add up extra wide battens so that I effectively add a new floor. You can see how extra battens are added in this photo (not my dinghy) . 100_0507 | Flickr - Photo Sharing!

As for the motor, I've just purchased a 54lb bow mount, and I'm planning on making a cradle to carry the 100AH battery just forward of the centreboard case. I figure the battery is too heavy to rest on the floor, so the cradle will have a cross beam resting on the thwarts, which I think will be better placed to take the weight.

thanks again for the help

Tom

Tom,

The brand of EPOXY is up to you really , I have used BOTE-COTE on my current boat and am happy with it,
but I believe that most on the market will do what you want , as long as you follow the directions as to mix ratios correctly.

I used a set of digital scales when mixing my resin , and perfect set off every time.

1 Tape fiber glass 50 or 75mm wide( I brought just cloth 200grm and cut the tape , it is cheaper.)
2 I would put the stringers on the bottom (outside) , you will not put your foot through the floors?hull as the ply is supported by the water to a degree, and this spreads the load to the hull as a whole.
3 internal floors : if you do not intend to sail the boat ,you could remove the center board case and make frames(6mm ply cut to shape) with 20x20 stringers and forget about the external stringers , or add the as rubbing strips I would look at adding a small skeg , as this would assist with steering .
Jeff