Could the association introduce a Joint Membership category for couples living at the same address? We sail together and like to swap helm/crew roles but helms are supposed to be members for events. 
If we pay two single memberships we get twice as much paperwork through the post, so how about an in-between rate eg £40 for joint membership - only one copy of magazines etc. would be necessary so it saves costs! At our club we have this and it counts as one membership unit with one vote.

You effectively have that with associate membership. If you own one boat, then you need only one full membership and one associate membership = £40, both can legally helm. Still get two magazines though.

thanks alan could not have put it better myself , quite a number of people do this