I'm thinking of putting in a through hull hose flush kit. Something along the lines of:

http://www.cpperformance.com/p-13742...connector.aspx

What is the best way to drill the hole? Do you start small and work your way up? Drill from the outside towards the bilge or reverse? I'm afraid of creating a hairline crack or a chip outside of the hole.

thanx

Are you planning on installing it in the transom or the side of the hull?

Either way, with a hole that big a hole saw is your best bet.

I start to drill from the outside in. Tape off the place you want to drill the hole with masking tape, preferably blue or green painters tape. Mark the hole, then begin drilling. Just use light pressure and go slow with the drill speed, let the drill do the work. Once you get through the fiberglass and into the wood you can lean on it a bit more, then back the pressure off some when the pilot bit starts to pierce the inner skin.

After the pilot bit pokes through the inside, I like to switch around and finish the hole from the inside of the boat. Again with light pressure and slow speed letting the hole saw do the work.

YEP, that would be how you do it , when installing this use marine silicone, NO 5200... because if you ever need to replace it it will ripp the gelcoat if you use 5200.
Marine silicone from WEST MARINE is actually a very good product and works perfect for this.

Run the hole saw in reverse slowly until you get through the gel coat. That and taping the area first will help prevent chipping and cracking.

Thanx, it will be on starboard side.

Drill it to size in 1 shot, don't work your way up.

X2. This works like a champ even in 30-year-old gelcoat.

I haven't tried going from inside out, but I'm thinking you'd really be depending on the tape to do that, since the saw would be pushing on the gelcoat at the same time as trying to cut it.

I didn't mean to go from the inside to the out. Masking tape on the gel coat helps a little and also protects the area around the hole.