Jamie just use some glass matt strips to rienforce the joints at the transom,shes looking good so far mate .I know you will probably be running on land and water but for on water you can extend your rudders so they enter the water and it will give better turns on water.My mate came up with some rudders that he could change to run on water or land if i can find the sketch of his idea ill post it.I think the idea was he can us both sets of rudders when on water and the water rudders can be either removed or folded up out of the way on land maybe.He made this boat using airplane floats with a large .61 nitro i believe but he never did finnish it due to some personal troubles,pitty as it was looking good.
here you go.