Water in engine bilge

[Howler]

Our sailboat has a Yanmar 4JH45 engine. The collecting pan under the engine (isolated from boat's normal bilges) has been bone dry during four years of operation. I recently left the boat for a few weeks and returned to find about an inch of fresh water under the engine. We're on the Great Lakes so it's hard to distinguish between "sea" water and "house" water. The water had no traces of coolant, diesel fuel or oil. I've run the engine since then and watched all the hoses and joints associated with the raw water cooling circuit for leaks. Nothing. And the collecting pan continues to remain bone dry. Same for the house water systems.

So the question is, what could have caused water to accumulate under the engine one time and only one time.

A few other observations:
- There's no evidence of rainwater entering the cabin or engine room.
- It was very hot during my absence (condensation? expansion?)
- There's an air conditioning system purge valve in that space but it's closed

Any guesses? Thanks!

[Networker]

On my boat (Beneteau 40CC), the cockpit drains to a hose through the engine room, and out to sea, and the hose leaks. So what looked like a bad seacock was just rainwater. Maybe you have something coming in from above?

[Howler]

Originally Posted by Networker

On my boat (Beneteau 40CC), the cockpit drains to a hose through the engine room, and out to sea, and the hose leaks. So what looked like a bad seacock was just rainwater. Maybe you have something coming in from above?

Thanks. Good hypothesis, but on our. 41.1, the cockpit doesn't drain via the engine room.

[GreenWave]

Where is your strainer for the engine water intake relative to all of this? Maybe it didn't leak while running, but it could have a very small drip (due to a crack etc).

[Howler]

Originally Posted by GreenWave

Where is your strainer for the engine water intake relative to all of this? Maybe it didn't leak while running, but it could have a very small drip (due to a crack etc).

It’s in a place that would effectively drip into the engine bilge, but I inspected it and it’s dry, as well as above the water line. Thx.

[Stewie12]

Did it rain whilst you were away ?

[Cheechako]

Sometimes a hard rain will get in a companionway crack, or a cockpit locker etc and flow to the engine bilge. Or: Is the packing dripping and does it flow there?

[RSB333]

Did you check the heat exchanger? Mine is on the aft end of the engine, hard to see its underside, but mine would drop seawater into the drip pan of the engine if it leaked.
RSB333

[Cadence]

You said it was hot, were the nights cool? It may have been condensation.

[MJH]

Originally Posted by Howler

Our sailboat has a Yanmar 4JH45 engine. The collecting pan under the engine (isolated from boat's normal bilges) has been bone dry during four years of operation. I recently left the boat for a few weeks and returned to find about an inch of fresh water under the engine. We're on the Great Lakes so it's hard to distinguish between "sea" water and "house" water. The water had no traces of coolant, diesel fuel or oil. I've run the engine since then and watched all the hoses and joints associated with the raw water cooling circuit for leaks. Nothing. And the collecting pan continues to remain bone dry. Same for the house water systems.

So the question is, what could have caused water to accumulate under the engine one time and only one time.

A few other observations:
- There's no evidence of rainwater entering the cabin or engine room.
- It was very hot during my absence (condensation? expansion?)
- There's an air conditioning system purge valve in that space but it's closed

Any guesses? Thanks!

Could it have come from your refrigerator/freezer?

~ ~ _/) ~ ~ MJH

[JimsCAL]

My stuffing box drains to the engine bilge. So if I have been motoring for any length of time, I will have a bit of water under the engine. Also after a heavy rain I will have some. Never figured out where it was getting in.

[capn_billl]

I just found a similar leak in a Leopard 44, same engine. Is was coming in the rub rail. banging against dock when bumper came loose cracked it at the hull joint under rub rail.

Rain would flow down rail, and through crack in rear of engine room at joint of swim platform (sugar scoop).

I fixed temporarily by 3m'ing top of rub rail.

fiberglass guy is going to pull rub rail, and re-glass next haul out.

I hope this helps.

[chasfgr]

Mine kept leaking a little fresh water after every wet week.
Finally found it running down the fresh air inlet, from instrument panel in cockpit to the engine room air intake.
Solved by having a swan neck instead of a straight tube, and drilling larger drain-holes in the bottom corner of instrument recess.

[auwekamanu]

The stuffing box?