I picked up a much needed rudder for an old fiberglass tandem I have. The back of the kayak has a flat spot big enough for the 5/8" wide, drilled mount for the rudder. But, how am I going to mount it? I mean, to hold the bolts or screws from a cockpit would require a 5 foot screw driver or socket extension. I am not sure if the ends were even poured or not. There is some kind of late 1970’s foam in each end. Do I use a lag bolt? Do they make like moly anchors for fiberglass? I want it to be strong and waterproof. The mount has 2 holes drilled (1/4") about 2 inched apart.
It might be easier than you think
Last year I bent my rudder bracket on my QCC, (long story which I won’t go into).
My very first thoughts were how the heck I was going to get at the nuts on the inside where the two bolts go through.
When I removed the bolts, I was quite surprised to find that they were just machine screws with a rubber washer to prevent leaking.
I would just drill holes the next diameter smaller than a stainless steel self tapping machine screw and then us rubber gaskets with them.
Perhaps Pat Onno or one of the pros will chime in here and help you out, but that is what I would do.
it does have some form of end-pours. Any FG boat that is seamed on the interior should have an end-pour for durability and to seal the seams where a tape seam cannot be apploed well. You might be able to ascertain the extent of the pour by thumping the hull with a small hammer or screwdriver handle and listening for a change in tone.
yaks had water proof pop rivets for the rudder plates . I’ve replaced ALOT of em from folks dropping the yaks w/rudders down as well as having em smashed on stairs an rocks . Water tight and available from many fastner companies as well as the better local shops that have repair parts . I’ve even used the regular pop rivets of aluminum with a fair deg4ree of sucess . I also put some silicone on the back of the plate and holes before riveting .
best to ya -Hope that helps