HELP - phantom leak in 1999 Wakesetter (sunsetter)

[99Wakesetter]

We have a 1999 Wakesetter that has a mystery leak which manifests itself in two ways:

- the back port/passenger corner carpet is soaked in the morning in front of the bench, but dry underneath the bench to the back of the boat, and dry from the engine cover forward (mid boat engine) - leading us to think the water source is somewhere forward in the boat, although the ski locker seems to stay mostly dry.

- when at the dock, the bilge seems to pick up ~5 gallons of water an hour

we’ve bypassed the heater, replaced the cooling hoses, and sealed the HDS box on the top side... 

any and all thoughts appreciated... 

[justgary]

It is possible for the lower part of the HDS box to leak where it contacts the hull. If you have a lift or trailer, you can fill the boat with some water to test that. 

Depth transducer, paddle wheel, raw water intake and hoses, and wedge plate bolts are all under water.  Oh, and the drain plug sleeves can leak also.

[justgary]

Oh, and of course, the exhaust ports, hoses, and mufflers are under water also. 

[csleaver]

Loose clamps are common places for leaks, but sometimes hard to find leaks can come come from the least likely places. 

The hardest one I've had to find was caused by a battery box that was installed, and then removed, by the previous boat owner near the edge of the port aft compartment in a small IO runabout.  One of the screws used to install the hold down actually went through the hull and caused the carpet in that corner to always be wet.  After lifting the carpet, a found a 1/8 inch hole that looked a lot like the world's smallest drinking fountain.

It is usually easier to find a leak if you can narrow down when it is leaking.  Does it only leak or leak the most when the motor is running, when the boat is at a certain speed, or does it constantly leak the same amount all the time?  Drying everything in the bilge areas and hunting down what area the water is coming from with a flashlight and a mirror (or camera/borescope) also helps.