|What you are talking about is "slopper stoppers". Usually they are made using two overlapping rubber strips along the keel line. If you can find an old windsufer you will see the basic principal underneath. |
However, once you add them to your boat, your boat will be deemed to be a drop keel by race commities. Your handicap will suffer significantly.
If you are having water coming up the wire and into the cabin, you can remidy this by removing the timber at the top of the case and adding similar rubber stips there instead.