Cool, and good point about the fender washer sizes. I found these bigger then normal but smaller then fender washer washers and use them. I got the impression that no metal washers are being used? If so, you should have s/s washers between nut and rubber washer in order to distribute the load over a bigger area of the under deck in the event of a large yank or a maytag session. Now if you did use s/s washers and said so in your response, then put up with me, I might have been dumped on my head once or twice too many times in the surf...but...somebody once said "use your head..." so I did!
best to ya buddy

: That is exactly what I did. I didn't use fender washers because I didn't want
: to have a lot of hull curve under the washer. I used rubber washers that
: were one size smaller than the screw. That made sure the fit to the thread
: was really tight and that the threads were sealed when I compressed the
: washer.

: I wasn't concerned with cockpit screws. Only the ones that went into the bow
: and stern compartments.