ferret30":3uta6ecf said:I'd consider trying an adhesive only (no screws) approach to holding the block.
I've just cut a Starboard™ block for my transom (removed the transducers, which were directly transom mounted, and will be repairing the disused holes before re-mounting them on the Starboard™ block) and I plan to mount it with four Weld Mount studs (they use methacrylate adhesive). I don't think the forces involved will overwhelm the gelcoat - at least I think I have a reasonable enough chance of success that I'm going to try it that way (of course one could also remove the gelcoat down to the glass if they wanted to).
Another option, perhaps.
Sunbeam :hot