I need to add a dump fitting for my bilge pump. I figured I would ask some questions before I mess something up   I want to add it right next to the two dumps that are already there, Before I start drilling the transom is there anything I need to watch out for? Is it best to drill from the outside in? Anything structural there that can be damage?

Thanks in advance,
James

Drill from the outside in and like Ray said, make sure to triple check the inside of the boat for any obstructions once the bit comes thru. Also use some blue painter's masking tape on the outside of the boat, it will help minimize chipping of fiberglass.

I had to also do this. Another tip besides the painters tape is that I made an aluminum flat stock JIG that located the hole exactly on the same plane as the other one so when you look at it they are even. I did this on the brigeport so both holes (existing, and new one to be) were spot on.
T.J.

I use a 4' level and frog tape, but same idea! 

Ray

Thanks for all the tips guys, I will be doing this on Sunday I'll let you know how it turns out. Stupid question but what size bit should I use for a 5/8 dump? Just want to get it right the first time 

Thanks,
James

Might sound stupid but I do the same as everyone else but When I'm starting the hole through the gelcoat I will run the drill in reverse to help with the chipping of the gel or paint, once past the gel I put it in forward and finish it up. Just measure your fitting to determine the correct size bit and slowly work up to the final size.

X2 on this

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