Here's another. My first boat, that wasn't the Old Man's, was a late 70's 14ft Shakespeare with a 3cyl Suzook 65. I went to town on it.
I had the deck pro painted Ford bright lime green, new seats, screen, floor and carpeting. When screwing and sikaflexing the floor in I thought that my s/s screws were a bit on the long side. I then checked the amount of void between the floor and the hull. Plenty and on I go. I then gave a carpet laying mate £10 to do a nice job of the nylon carpet.
Ready to launch now, back her in as far as poss and give her a shove. Umm, bunked trailers are always a bit reluctant. Gets in, fires up the Suzook and gives it a bit of astern, no good. Give it flat out astern, still on the trailer. Hauls it out wondering WTF was the matter with the thing. I rocked it from side to side on the trailer and all became apparent. I'd screwed the hull to the bunks.
The floor at the edges sat over a spray rail, and directly on the hull. I'd only put about 1/4" of four screws through into the wooden bunks, but it was enough to hold her fast.
Shorter screws and gelcoat filler sorted it, i never got the Suzook to run properly though.