I have a 25 year old GRP speedboat, which i am renovating this winter, i have no problems other than the fixing screws / bolts for the front bucket seats, they have dissapeared in a cloud of corrosion, only a couple of rusty sawn off threads remain. I think i know how to do it, but i would rather trust someone who lnows the answer, rather than me guessing, can anyone help.

Ray

Ray Smith, November 2009

HI,assuming its a plywood floor,buff the remaining rusty bolts on the floor flush,make up four metal sheets 4"+4" "as many as required"
drill the "centres" for the new bolts that will fit facing upwards on the plate, drill the holes in each corner of the plate the size you need for the large wood screw bolts that will screw downwards into the floor drill the floor first so as not to split the plywood and also an indicator for the depth of wood screw that you will need so as not to screw it through the hull. make sure there is a small recess on the plywood floor centred for the final position of the plates to the floor for the bolt heads to fit into facing upwards in the centre of the plates secured with a locking "nut or welded", the plates can be screwed into the correct position with a cardboard template from the seat just to make sure it all fits .
I had an old fletcher speedboat and this worked a treat. Good luck Ray

Bigman, February 2010