Water leak - Bilge area - 2004 38 Fastech
 

Posting for a friend - hence my user name.

2004 38 Fastech 525 engines with extension boxes - Taking on water at cruising speed and above. Water entry location is coming from the drivers side rear engine compartment area - near the back of the rear seat. where all the hoses come into the bilge area. Hoses appear to be the raw sewage discharge line? Maybe some vent hoses? The leak isn't coming from the hoses, but somewhere up there draining into the bilge area.
Boat is stored in a covered boat house - so no rain water.
Doesn't leak when sitting in the water or running the engines.
Both Seacock valves are in closed position
Get about 10 gallons of water on the starboard side only when cruising. I ran the boat at fast idle with the engine hatch up and you can see the trail of water start to run into the bilge. I'm thinking maybe the AC water intake is leaking under pressure in the hull? Anyone ever have similar experiences?