This photo is showing the spot for the new seacock & thru-hull as chosen from inside the vessel.


1- Once you have chosen your spot drill through the hull from inside using a 1/4" drill bit. The reason for the 1/4" bit is that it matches the size bit used on most hole saws.


2- You then drill into the hull from outside using the proper sized hole saw to match the thru-hull. Start the hole saw in reverse as I have done here and you get no gelcoat chipping. Once through the gelcoat switch to forward and drill up through the hull making sure you are perpendicular to it.