I noticed that the bow thruster on a 330 I am looking at was installed by cutting the hull and then cauking (5200?) the seams. It appears to be sea worthy. Is that how GW does their thrusters? If so I will not worry so much.
were you looking at a boat that had a factory installed thruster? if so, gw actually builds the hull around a plug. then they later install a tunnel (basically up against the exterior of the hull) and then "glue" in the keel insert. the integrity of the hull is maintained. if it is after market, you better check it well. ron