Trying to locate a water tank leak in a 500 DA

[Steve500dancer]

Ok well a couple of years ago I noticed fresh water in the compartment that houses my shower sump box. I traced it down to a crack in the top of the 150 gallon water tank under the salon floor. I repaired the crack with 5200 and it seemed to hold well. I also new that the tank had to crack for a reason. I removed the vent hose and found it was plugged. I blew it out and thought I had taken care of my issue

Well this spring I noticed that the area around the sumo had a couple of inches of water in it again. This happened after I over filled the tank. I had completely forgotten that I was filling it up and once I heard the water come out of the bilge pump I shut it down.

On Saturday I noticed I still had water in the same area again. I got it all vacuumed up and started the hunt for another leak in the tank. When I was vacuuming it up I found water coming into the bilge area from a 1/4" hole in the stringer between the water tank and sump area. I stuck the vacuum hose on the hole and managed to get about another 6 or 7 gallons of water out from under the water tank. I dried everything up and left about 1/2 a tank of water in the tank and went home. The next day the area was still dry. This tells me that the leak is somewhere in the top half of the tank.

Ok here is the crazy part about this deal. The filler tube is 1 1/2" and the vent tube is only 3/4" how in the world can the tank overfill with out major expansion and eventually cracking. The air vent is also located on the far end of the tank and comes all the way from the ,aster state room to the galley sink area and the filler neck is almost a straight shot into the water tank. Sounds like a pretty crappy design to me.

So know I am left with trying to find where the water is leaking out from when it is filling up or full. My idea is to add red food coloring to the tank and fill it up slowly and use my gopro camera to look for a leak. Hopefully it is something on the top of the tank or from a fitting, if not I am screwed and will have to pull the tank out of the boat. This is one hell of a job.

Oh and here is the other stupid design. The hole at the stringer under the tank is at the same level as the the bottom of the sump box area. If water gets in that area, every time the boat moves it will let the water run back and fourt and back up under the water tank that is also full of foam from the factory. That means it can't build up and trigger the float switch.

Any thought or ideas would be a a great help. I also have a buddy in Europe having the exact same problem with his 500da

Thanks in advance
Steve

Sent from my iPad using Tapatalk

 

[Sea Gull]

Is that a porcelain light bulb socket below all that plumbing? If so, I'd remove that before fixing any leaks. As for the tank, it might be time to replace it and the vent and fill connections. The basic set up seems ok to me and similar to my 58 and 65. I have also overfilled the tank and had water come back up the fill pipe and out the vent, but never did that cause water inside the boat.

You want water to move from one bilge compartment to the next, for safety and so you don't need a bilge pump in each section.

 

[bahamabreisus]

Steve, I get water in the same are once in a while, but it comes from the sump overflowing, because of slime build up on the float. Clean it and the problem is gone. The vent hose is plenty large enough, remember water is thicker than air. Hope you problem is not the water tank, thank would be a messy job.

 

[Steve500dancer]

Is that a porcelain light bulb socket below all that plumbing? If so, I'd remove that before fixing any leaks. As for the tank, it might be time to replace it and the vent and fill connections. The basic set up seems ok to me and similar to my 58 and 65. I have also overfilled the tank and had water come back up the fill pipe and out the vent, but never did that cause water inside the boat.
You want water to move from one bilge compartment to the next, for safety and so you don't need a bilge pump in each section.

Yes p/o had wired light bulbs everywhere at some time to use as heat lamps in the winter. I have disconnected all power to them. They ran on one circuit that he had labeled "heaters" I just have to finish cutting on the wires out. And remove the fixtures.

Correct but it can't build up enough to trip the float switch. It just rolls back and fourth from one compartment to the other. I am adding a second float switch next weekend. I am going to use the water witch and just in case it continues to leak water I can set it much lower to remove water at 1/2" instead of 2"

 

[Steve500dancer]

Endless seas you just tried to send me a private message and my box was full. I emptied it if you would please re send.

Thanks
Steve Bone

 

[Steve500dancer]

Update, took another trip to the boat last night to work on the helm pump and check on the shower sump area and it is still dry as a bone. So far I think with 1/2 a tank of water I am in good shape. I am going to try and slowly fill to 3/4 later in the week and see how that shakes out. Really hoping that this issue was just an overfill issue.

Steve