a rattling hull

nikobrogna

nikobrogna

New Member
hey guys. I was recently given a 1992 sunfish hull. It is in satisfactoy shape, but needs a little work. One problem that I have encountered is a weird rattling noise that happens when the boat is moved or flipped over. It sounds like decent sized chunks of something, maybe loose flotation foam? How could I fix this? Does anyone know if I could melt the foam out with acetone or other solvent, and then use airbags instead of the foam? Any easier ways? Thanks,
nick
 
The foam blocks actually supply support to the deck and hull more than "flotation". You can "reset them" using some of the can insulating foam products. Figure using 6" posts and doing the work before actually mounting the port ring to give the little extra room for arms, etc.
 
Foam-in-a-Can is only a short term fix. I've tried it and it did not last a full summer. It is better to use a two part foam that sets up much harder than the can foam and locks the blocks in place. Not only has it lasted a full season, it also survived a 3000 mile deck up trip with out any loss of rigidity to the hull or loosening of the blocks. See Yahoo SF Sailor, Files, Foam Block Reset. It is a relatively easy fix, just takes a little time to do. The usual location for the forward 6" port, behind the splash guard, will allow you to reach most of the forward blocks which are the normal ones that loosen.

If you remove the factory foam blocks, you will weaken the hull and shorten its life to just a few months. They are an important structural part of the hull and need to be connected to both the deck and hull (ie. 2 part foam). Plus, if you ever decide to race your hull will be illegal (rule 3.1.3).

Another possibility is that one (or more) of the backing blocks or plates have come loose and are causing the rattle.
 
If the boat has inspection ports that rattling could also be nuts! I live in an area where squirrels find Sunfish hulls to be super-duper depositories for Black Walnuts. ARRRGH! I have no idea how they do it, but they even get them up into boats stored upside down, off the ground.

The foam blocks make it quite an effort to get them out. Lift the hull so the bow tip is down and all nuts roll forward. Then lower perfectly horizontally so the nuts will roll back, between the two forward foam blocks. I have one hull where I simply can't get the last one out.

It could also be screws or wood backing blocks that have dropped from previous owners repair efforts.

Good luck.
 
Gail,

Had the same thing when I got my '69 SF in 2003. Every time I moved the SF, something would rattle and roll. When I finally put in the 6" port behind the splashrail, there were 2 large nuts about the size of walnuts (I have no idea what kind) laying in the keel grove under the port. The previous ower had cut the rear 5" port to do rudder upgrade (not completed) and had just set the port in place. He said he had had to place it back in place a few time over the years. I also had a colony of ants (carpenter) living in the rear foam blocks, gave it a good spray, put the port back in place and later was able to vacumn the hull clean.
 
The rattle could be the wood block underneath the handle. Mine came undone after 30 years of ownership. The wood is held in place with a fiberglass strap that is glassed to the deck. When the strap comes undone so does the block. Put an inspection port in and have someone tilt the boat. Incidentally the sound will definitely sound more solid than a loose foam block would.
 
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