Andy,
Welcome to the list. Pictures are always helpful in trying to describe your  
problem, but makes it easier for us to understand and decipher. Solutions to  
your problems will follow.
About the center board cap. It has a rubber gasket which should not be  
replaced with anything else. Our experience with the boat is that it almost  NEVER 
is the cause of leakage. Forty or more bolts hold it in place and it does  a 
wonderful job.
 
Rummy
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