The admiral acquired a 1982 Lund S-16 Deluxe from her father. It has a snap on cover supported by two battens. The cover is in bad shape and needs to be replaced. We need something that can be left on the boat while it is tied to the dock at the summer cabin. The cover needs to stay in place and be able to keep most-to-all of the rain water out for about a month at a time. What she is finding are semi fit covers that have elastic hems and a pocket for a support pole. Can snaps be added to these? Will they be able to be tight enough? Can the support pole be sufficient to shed water if the cover can't be made tight enough to rest on the battens? Or, are we looking at a custom made cover?