This is an American fiberglass 21 foot sailboat. I am redoing the whole back end of the boat and before I put the rudder back on I want to figure out how it originally came from the factory. It has a swing up rudder that attaches at the top of the transom. The transom has a cut out for the rudder to lay down flat in. I believe someone along the line modified the way the rudder works. Inside the cut out there are holes on either side that were patched badly. I cleaned it up with fiberglass. Now that I'm putting the rudder back on I see that they were probably from the factory. Somebody installed brackets on the transom that would either hold the rudder down when in use or up to take the rudder off . I think the holes enabled a pin to go through the cutout to hold the rudder down. First question is do I even need something to hold the rudder down when in use. If I bottom out the rudder can swing up but if it's held down, it will impact and destroy something. Second question, I believe there was a pin that went through the holes in the cut out to hold the rudder down. I can redrill those holes but the metal pin would be going through fiberglass and wouldn't have any support to keep it from Ovaling out the holes . Last question, my rudder is huge and hangs down below the bottom of the boat and weighs a ton. I was thinking of getting two rudders from maybe a Hobie cat and doing a dual rudder set up. Most of the other sailboats my size appear to have thinner and smaller rudders than mine .