Bill,
I don't know how you sail, but I could never store anything under the  
cockpit seat as heavy as an anchor. The only object I keep under the seats is a  
small plastic container with my anchor line in it.....no chain. That slides  
around enough as it is. I can't imagine trying to keep a three or five pound  
anchor secured under my seats. You must sail flat most of the time.
 
Rummy