which caulk or sealant to use around that aluminum bang plate and the two plastic corner pieces on the transom ? Any success with a particular product ?
To do it properly you'll have to get the aluminum bang plate off. Not sure this can be done without cutting it. GW uses a plastic one now. Could cut the existing off, seal the joint and then install the new plastic bang plate (may need to bifurcate it if done with engines on) and bond it in place (no screws).