If youre trying to drill the transom, any dealer has the drill template with guides on it fo the proper angles. Its worth it to pay them a few bucks to do it or possibly rent the template.
Actually I am adding a piece of 1/2" aluminum to the exterior of the transom for reinforcement. It's a 1973 boat and the transom is getting soft in the engine mount area. I would like to pre-drill the plate.
how about putting grease or lipstick on the ends of the bolts already in the transom then placing the plate against the bolts transferring the bolt pattern? sounds corny but it has worked for me on other things.
