fresh water drains to bilge

[aquapore]

M Bav 41 has just started to drain drinking water into bilge - 50 l over night.
The pressure pump activates momentarily every sa 5 min for about 1 sec.

The bilge under  the motor is dry.

I cannot find any evidence of leaking around the pressurizing pump or any outlets.

Gravity would suggest that any leak from the tank, hot water system area would be captured by the bilge under the engine.

Any suggestions on probable cause would be appreciated.

Regards

Aquapore.

[elias]

Hi ,
It has happened to me too ,leak was in the water heater main nut.

[sean c]

I had a leak in the transom shower plumbing. Try turning the tap off on the transom, not just the hand held bit.
Have a look in behind the back panel into this area. It drains to the main bilge.
Sean

[Happysailor]

In the later models Cruiser, indeed the aft shower is very suspicious. The selector cock is a bit tricky and often the showerhead press button becomes seized. In our boat, the previous owner had it not properly stored for winter, which resulted in a cracked handle of the shower. Easily replaced at low expenses, but easy to loose quantities of water there

[aquapore]

Thanks for your responses.
I don't think it is the aft shower or hot water as that wound drain in the bilge under the motor which is isolated from the main bilge which collects the water.
I have made further investigation and the water starts to drain it the forward section of the bilge.
I notice an additional blue line which passes the cupboard under the sink and then mysteriously disappears into the furniture. That is 3 line 1 red and 2 blue enter the sink cupboard and two lead on the second head after servicing the sink faucet. I cannot see where the extra blue line goes. I don't want to start opening up the wood work.  I am looking for a piping diagram. Appreciate any help.
Regards

Aquapore

[symphony2]

First are you sure about draining into the bilge area under the engine? Not my experience with a 37 from the same era. The blue pipe going forward is almost certainly the feed from the front water tank (which in itself is often a source of leaks) to the changeover valve.

[UP]

Some freshwater leaks I've had:
1) Pinhole leak in 15 mm tubing (I only found this because I put a flashlight behind the leak to work on a different project and the fine mist gave a nice "halo" in the light) - very hard to find, but this is not going to leak 50L overnight;
2) Aft shower hose dethatched from the shower head. I pumped 250L+ into the boat in about an hour;
3) Various leaks from old or poor quality 15mm push-fittings. My boats whole plumbing system is made up of 15 mm push fit tubes and push-fi-fittings. Some degrade over time, others are simply poorly made and on some occasions the 15 mm hose itself becomes damaged at the sealing joint due to repetitive use (there is a metal "claw" that keeps the pipe in the fitting);
4) A leak from a self made 15 mm stopper which was fitted into a push-fit T-joint.

A tactic I would use in your case would be to segment the boat. The plumbing will likely run either clockwise or anticlockwise from to the pump to rest of the boat. If possible, I would shut off half the boat from the water supply and wait for the pump re-pressurization. If this occurs, you know that the leaky part is likely in the pressurized segment of piping, not in that which you plugged.

[SYJetzt]

Thanks for your responses.
I don't think it is the aft shower or hot water as that wound drain in the bilge under the motor which is isolated from the main bilge which collects the water.
I have made further investigation and the water starts to drain it the forward section of the bilge.

The motor bilge only collects fluids from the engine. If you have a leak in the aft part of the fresh water system, it will drain to the central bilge thru the laminated stringers.

[aquapore]

yes, Symtphony2 is right - the blue line moving forward is connected to the forward water tank. I was expecting a different type of hose as a suction pipe.
I am the second owner of the boat and it may be some changes have been made. The change over valve is brass 3 way "L" port valve which appears to be plated brass with 38mm braided hose connections - something you would buy at a hardware store. It appears to be very "agricultural" in design and construction. The valve is not attached other than by the pipe work.
I will investigate further.

There is no water under the motor. Does that rule out the transom shower and the hot water tank and fittings aft of the motor.

I will dry the bilge and pour water down the drainage faculties at various locations to try to find the source of the leak.
I will also check put various location suggested in reply.

regards
Aquapore

[jeffatoms2]

We too have had this a number of times.  A few things we learned along the journey is that toilet tissue wrapped and rubber banded around dips in pex and all pex connectors were the pathway back to the source of each leak.  Toilet tissue,  particularly marine TP, is a heck of an indicator, sorta like a canary in a coal mine.  Once wet, it shows itself and it will not go back to looking dry; it either stays wet or looks like a mushy lump.  Put enough of these on your system, and once you find the first wet one, trace it back to the upstream connection.

At 25 years, this is sadly a part of owning an older boat.  We just left them in place and added the "leak" check to our regular boat tasks.  It would be a good idea to have a buck of Whale branded PEX connectors and fittings (not Sharkbit Imperial and Metric sizing are not interchangable) and various lengths of blue and red PEX at the readdy.