2001 356 aft cabin getting water in the rear bilge

[Ron@murr.biz]

I am getting salt water in my rear bilge while underway. I just can't locate where it is coming from. While in the marina its dry. The dripless and rudder shafts are not leaking. The air conditioner drain into the sump is working. I caulked the outside molding thinking it may be coming in there no luck. Sometimes it's only a 1/2gallon other times its 2 or 3 gallons. does not seem to matter if its calm or rough seas while underway. Any ideas?

[bud37]

Welcome to the forum......have a look at your engine room vents and for sure check the exhaust hoses especially near the hull exits....considering it is dry in the marina.

Do you have muskrats/critters that like exhaust inlets where you are ?

[Ron@murr.biz]

Thanks...should have mentioned that. I have checked the exhaust back there and can't see any Leakes from them either no critters on board the boat it is in Newport Beach Calif.

[tomschauer]

Have you verified underway that the shaft seals are not leaking?

[Viper]

Welcome aboard.
I don't recall if water in the bilge of that model can run unimpeded from one section to another. If it can, it can be originating anywhere. If you've ruled out the shaft and rudder logs, exhaust, AC, etc., I would run the engines one at a time above idle and look for leaks. It's likely that you have closed cooling but there will be a raw water circuit that should be inspected.
What engine package do you have?
Did you check the shaft logs in gear, and the exhaust with the engines running?

[True-North]

My 355 was leaking through the propeller shaft strut mounting bolts.

[Viper]

Ya anything penetrating the hull is suspect.

[Ron@murr.biz]

Thanks for the responses. The way the boat hull is layed out water can’t flow between the compartments and both the engines and drip less shafts are in the mid cabin. I’ve check the starboard prop shaft bolts easy to see thru an access hatch. I will see if I can get to the starboard side I think it will be under the water tank or air cond. its under the aft bed.

[pondiscio@gmail.com]

As noted above... It could be coming from anywhere. Especially since it only shows up after you have been under way. Check you hull grid for limber holes. The grid is hollow and does allow water to flow between bilges. It's likely coming from another part of the hull and when you are powering up and the bow rises, water drains to the back of the boat inside the grid. Welcome to the part of boat ownership where you crawl into every corner of the hull to find the leak.

[Ron@murr.biz]

Thanks check both shaft struts and their dry. Can you explain were or what the grill hull is and located and limber holes I assume the holes are the ones that allow water to flow between the stingers. One more weird thing is my boat tilts forward. So the water never reaches the aft bilge even underway. I have to manually pump it out every time. The water pools under the rear holding tank close to the shower sump, but it is salt water so you just can’t get a good look under that area. The motor are dry with no visible leaks.. I’m installing an extra Bilge pump by the rear holding tank to pump the water out. Thanks everyone