Originally Posted by Mr Flibble
Thanks for the advice guys. I've ordered some 316 Stainless M12 coach screws and will screw these into the deck along with some 3M 4200 to act as a bonder and sealer. Shortest screws I could get were 50mm so will need to pack out with some washers. (I'm assuming Humber decks are 1 inch ply). Did a test with some wood I had spare and a 12mm zinc plated coach screw I had and by god it's a strong grip it gives.
If you speak to Humber they are very helpful they will tell you deck thickness as poly said I would think 18-20mm thick ,if you pilot drill , screw your bolts in till max thread has gone into the wood then take out and cut to required length no washers needed .humber will probobly give you a patten allowing the full screw length to go in anyway I don't know your boat but my deep v has at least 150mm between deck and hull where you would fit a bottle rack.best speak to humber for piece of mind.