check the archive
there was a thread on this recently. do a search. they were talking about some engine valve thingy. the alternative is the swing keel fittings. check to see if the water is salty or fresh. Also, to check for leaks, read the Don Casey books about pressurizing the cabin with a leaf blower and using soapy water on all your fittings. On my boat the leaks are at the shroud chainplates and right up at the bow, too.
