I guess that sounds a bit obscure, here's my problem...
I have a catamaran with fibreglass sheathed timber rudders that slide up and down in a cassette. About a year and a half ago I set up a jig on the rudder cassette and drilled four holes in the rudder so I could pin the rudder-blade at different depths, rather than just lashing it in place all the way down.
This has worked fine so far and enables me to motor into shallow waters without having to hang off the back holding the rudder up, but I want to strengthen the holes. At the moment I have just sealed the holes with epoxy and I am worried about water ingress.
My though was to bore out the surrounding timber and replace with high strength glue-powder epoxy, but I need to retain the orientation of the holes so they match-up with the holes drilled in the rudder cassette. My thought was to drill halfway through with a 1" auger drill bit, fill with the epoxy paste, and then use the hole on the other side to re-drill the hole. Then repeat the process on the reverse side.
This is where you guys come in... Any other great ideas of how to do this? I have to do it at home so locating a jig on the curved surface of the foil would be difficult to get right. Also, the rudder cassettes are near impossible to remove so I can't take them home too.
Looking forward to hearing your brilliant solutions to my problem... 
Sounds like a sound plan you have. One addition to it would be to make a jig replicating the cassette, out of suitable ply and oregon ends, so that the drilling angle is accurate enough done in your shed. Assume the 4 holes are lined up in the same vertical line - or same straight line parallel to the cassette forward and aft opening sides if the transom is sloped a bit. So the jig would only need to be (say) 150mm deep and do each hole separately. Or if you had to make the jib deep enough vertically to cover all 4 holes it would not be a big deal.
Other thought is to epoxy glue a stainless tube in at each hole - would last longer than the epoxy glue strength fill. Assuming the pin is stainless. Get tube the same grade - ideally 316 - as the pin. Edcon should have the size you are after.
