Where is the Leak in my Water System ?

[danleach]

Ok, this has been making me crazy for a year and I need the power of the hive mind.

On my 35 foot 1981 vintage sailboat I have two water tanks, port and starboard. The lines run to centerline, and each has a valve before the T joint where they run off to my pressure water system.

My wife and I have noticed that when we're running on the port tank, our bilge pump cycles a lot more frequently. About every 30 minutes. When we run on the starboard tank, no cycling of the bilge pump. And we're in the marina, no heeling action at all. I've searched everywhere looking for a leak, but can't find one anywhere. The
Port tank is dry on all sides, dusty almost. And the fact that there seems to be no leak when the port valve is closed would lead me to think the tank and fittings are fine, and the issue has to be downstream somewhere. But the fact that when we run on the starboard tank, and have no leak, would indicate that there is no issue with the starboard side or the water system past the t-connector.

Ideas?

Dan

[mesailor]

If you can't find a leak in your water tanks system, maybe they are in fact OK.

Could it have to do with your bilge pump and its output loop. Often the loop is higher on one side of the boat. It could be that the loop is not high enough. This could let water pass back into the bilge.

It would explain why there is more pump action on one tack but not the other and not when the boat is vertical.
Good luck
Dan

[skipmac]

Just so I'm clear. From each tank the hose leads first to a valve that is just open or closed, then from the valves there are lines to either side of a T-fitting (no valve part on the T).

When using the port tank the bilge pump runs, stbd tank it doesn't. Port tank valve closed (and the port tank full?) the bilge pump does not cycle.

Have you tried this experiment. Fill the port tank, open the valve from the port tank and leave it open when you will be away from the boat and not using water. When you come back is the port tank empty or at least less full?

If it is less full and you repeat the experiment and the level stops at the same point then look for a leak at that level. If the tank drains all the way then either a leak on the bottom or somewhere downstream.

One other thought. If the lines come together at just a T without a valve then even when you are using the stbd tank you will have water at every point in the system up to the outflow side of the valve on the port tank side.

So if you confirm you are losing water from the port tank then the leak must be upstream from that point. If not in the tank is it possible that the valve leaks when it is open?

[danleach]

Thanks MeSailor. But I know it's not the bilge output loop. This behavior isn't happening sailing....it's at the dock...no heal to account for difference.

Skipmac, Your first two graphs are accurate. But I want to be clear, it's the bilge pump is not running continuously....it's going on for about 20 seconds every 30 minutes. But when the Port side tank valve closed, using starboard water tank, the bilge pump goes on about maybe once a day for a short cycle. What I consider normal operations.

I think your tank fill test is next on my list. And yes, you are also correct that with no valve on the T.....when running the starboard tank I do have water all along the system up to that closed Port side valve. The port Valve, the stbd valve, and the T joint are all together on midline under the cabin sole, just aft of the mast step. If that port valve is leaking when open, it will be easy to fix. At least there's that.

Well, Off to test.

If anyone else has ideas....feel free to share.

[cwyckham]

I'm truly baffled. It shouldn't matter which one you're using, just which one is full. The entire system will be wet and able to leak no matter what tank you use of they're both full.

I assume that both tanks are full but using one or the other makes the difference? Weird

[sabray]

How about checking vent fittings. Do the tanks share a vent. Is one tank higher then the other.

[skipmac]

I think the fact that you only get the symptoms when the valve to the port tank is open and how the rest of the system is connected to the T isolates the problem. Unless something really weird is going on the problem has to be in the port side valve or upstream from there.

[danleach]

Yep, it is baffling.

Sabray, The tanks do not share a vent, and the vents on both tanks are clear working perfectly. The tanks are identical, and located under the parallel facing seatees on either side of the Salon of my boat. Perfectly equal height, size, and distance from centerline.

Skipmac, I'll be trying the fill test tonight overnight. And I'll be checking the valve very closely....but I assure you it's not that I've overlooked it before.

Thanks all.

[Dreaming Yachtsman]

Originally Posted by skipmac

I think the fact that you only get the symptoms when the valve to the port tank is open and how the rest of the system is connected to the T isolates the problem. Unless something really weird is going on the problem has to be in the port side valve or upstream from there.

I agree with skipmac that the problem has to be upstream (tanks side) of the port valve SEAT. Without knowing they type of valve, I would suspect the packing gland on the port tank isolation valve. Since you stated, "And I'll be checking the valve very closely....but I assure you it's not that I've overlooked it before" you have already had this same thought. Try wrapping a paper towel around the valve or placing it under the valve then opening the valve. If there is a leak, the wet spot on the towel will identify it quickly.

BTW, a picture of the valves, tee, etc. would go a long way toward explaining the setup.

[danleach]

Ok, don't ask me how...but now it seems to have stopped leaking. That just pisses me off even more. Sigh.

Thanks for all the comments folks. I'll let you know what happens next. I'm expecting complete blowout when I'm cruising off BC's Sunshine Coast in two weeks. That would be "boat-like".

[zeehag]

check all yout hose clamps. check all connections. check all hoses. something is leaky. my feline found my leak and acted as if he was going to be in a fight--sounded to him like a hissing gato. good bubba.
good luck finding your leak--i bet is a connection or a hose clamp somewhere-mine was a tiny pinhole in the hose just under the hose clamp.

[sailorchic34]

The valve stem packing may be leaking or there is a crack in the valve body. A bad ball valve could seal fine closed but leak when open

A gate or globe valve could have dry stem packing that leaks till the gasket material swells a little from the water leak.

Only place the leak can be is at the valve

[skipmac]

Originally Posted by danleach

Ok, don't ask me how...but now it seems to have stopped leaking. That just pisses me off even more. Sigh.

Yes, isn't that annoying. It's the corollary to "if it ain't broke, don't fix it". Well if it ain't broke, you can't figure out how to fix it.

Originally Posted by danleach

I'm expecting complete blowout when I'm cruising off BC's Sunshine Coast in two weeks. That would be "boat-like".

Of course, unless the leak chooses to reappear at an even more inopportune moment. Make sure you bring some extra water in jugs and bottles for when it happens.

[bobconnie]

Ahhh when ya cruise use the tank that leaks first !! that way if it leaks on your trip ya have some to use till ya can refill the leaker!! I tryed useing food coloring in one of my water tanks that had a leak I could not seem to find !! Used Red, and ya know it took no time to find it after that !! just a thought

[skipmac]

So Dan, ever solve the mystery of the leak?