Sea water strainer Install
Are you sure you need an external screen? I know you have the internal water filter basket (either a Groco, Forepar, etc basket).
I know most people that race wouldn''t want another "protrusion" sticking out of your hull. I have gone dozens of years without an external screen, and I know most boats around here don''t have one. Are you running into problems where your boat is located? Is there a lot of eel grass or something clogging your intake?
If you really wanted to put one on, you already have the thru hull so you can just add the Groco ones I have seen that are 2 pieces. Its a slotted strainer with mounting ring. Take a look. ( http://www.groco.net/catalogpage.cgi?id=590 )
What you could do is just clean the bottom paint down to the gell coat and then just attach the ring to the hull with 5200 and secure the mounting ring some how while the 5200 sets up (This stuff is pretty sticky tenacious stuff). Don''t forget to tape over the screw holes that will be used to attach the slotted strainer, you don''t want them filled with 5200.
Paint the whole thing with bottom paint then all you''d have to do is attach the slotted strainer with the 4 or 5 screws.