holding tank not water tight?

[sandiegoguy]

I have a 4600 SCB and I decided to "flush" the tank and fill it all the way up, wait for the red warning light to come on and pump it out. Well the red light never came on so thats another problem on its own.

But I noticed water starting coming out of the holding tank and I'm not exactly sure where. I think at the top somewhere. Does the tank have a big lid on it or is it a solid piece? It seemed to leak as if it had a lid and it has sort of a wooden brace on top of it like it's clamping down on a lid.

I shut of hose off real fast! I stunk up the utility cabin and then had to try and soak it up.

Luckily it was just clear water with a mild unpleasant smell but if it leaks water then how is is air tight?

[mmwjr]

The tank is typically two pieces fused together. There are penetrations for plumbing; waste in and out plus a vent. You also have one equipped with a float although does seem to be working. I suspect the vent penetration at the top is leaking but it may be a crack as well.

[sandiegoguy]

See attached image file for my setup.

Were most of the water came from the overfill I marked in red on the image.

It looks like the wood piece on top, holding it in place, comes off or at least tilts pretty easily so I guess I will remove that and try it again. I read someone suggesting use blue toilet bowl cleaner and a hose and fill it up to find the leak location easier.

I was using a flashlight to check the level of the water in the tank as I filled it up. I noticed it filled up and still nothing, no red light, no leak. Then another minute or two went by (still filling) and I saw decent dripping. I felt like the water went beyond the tank before it started leaking just from the time it took.

Noticed the vent penetration and another line is way in the back. Unless my boat was tilted for it to run to the opposite corner I don't think it could be those. I feel like the tank filled up and no leaks came but it went higher like maybe to the macerator and something there leaked. I felt around the filter cartridge and felt nothing.

Or I guess there could be a crack at the top!

I'll try again later but just wondering if the blue bowl cleaner is a bad idea since i'd have blue water leaking everywhere.

[mmwjr]

Since its going to leak into the bilge I would just use food coloring dye mixed in the water.

[dbriceno]

Last season I was getting a horrible odor in the salon from the holding tank. I then had all my sanitation hoses changed along with a rebuild of toilets and vacuum generators. Part way through the season it started stinking again. It turned out to be the vent fitting on the tank had broken. Got it fixed a couple weeks ago. Smell is all gone. Something for you to check

[TJK]

sandiegoguy,

I understand that it was unintentional, but you should never have the holding tank filled up to the top. Now the water probably got into the carbon filter and it's been ruined.

I suspect the water might have leaked from the vent/carbon filter fittings.

[sandiegoguy]

Originally Posted by TJK

sandiegoguy,

I understand that it was unintentional, but you should never have the holding tank filled up to the top. Now the water probably got into the carbon filter and it's been ruined.

I suspect the water might have leaked from the vent/carbon filter fittings.

Yeah, it was a hindsight moment. I need a new filter anyway and I actually hope its a leak from that area because that is something simple. But that brings to question if its not water tight then it's not airtight ? and something needs fixed/tightened/etc

I did find a tank monitor that will display tank levels without drilling into the tank. It's a tape you put on the outside and it somehow measures water levels.Easy cheap solution so that won't happen again.

[sandiegoguy]

Update to this topic. I finally got a chance to look into this holding tank issue. The smell seemed to slowly get worse. So I removed the things attached to the wood brace on top of it and lifted it up (luckily they were smart enough to put hinges on this wood piece) and i found this black lid. I slowly filled up the tank again with water/blue dye and a bunch of lighting.

Sure enough the water came out of this lid. I removed it (6 screws) and it just left a large 7-8 inch hole in the tank. The lid had a small amount of sealant on it....really thin layer. So i cleaned it all up and used a whole tube of new sealant and screwed it down into place. The adhesive ooozed out of the sides as I screwed it down and I'm hoping that is taken care of. I checked all fittings/hoses and didn't see any issues. The next day the boat seemed much better by the time i left. The test will be next time I visit the boat and walk in after being all closed up for a week. I'm hoping it just smells like a boat.

[jimq26]

Those round access hatches usually have a rubber O-ring that's designed to make the screw in hatch portion air and water tight. I suspect that also may be worn out.

Take the measurement of the actual screw in hatch portion and check your local WM or Defender etc. for a replacement O-ring.

[sandiegoguy]

Originally Posted by jimq26

Those round access hatches usually have a rubber O-ring that's designed to make the screw in hatch portion air and water tight. I suspect that also may be worn out.

Take the measurement of the actual screw in hatch portion and check your local WM or Defender etc. for a replacement O-ring.

It did. I checked it over and it looked fine. But I did use a thin layer of black silicone adhesive around the oring and tightened it back up. I don't ever plan to open it up again. If there is still a problem I will just replace the tank and all hoses so this was sort of my last ditch effort.

If there is still an issue when I go back to the boat I will fill it up again and see if its leaking at this lid or maybe a 2nd/3rd location. I'm pretty confident it took care of the issue.

[jimq26]

Good show. I'll bet it won't be a problem now.

[pirate]

Just FYI I had issues with smell and found out the pump out caused the the tank to collapse. This caused the bottom hose fitting to crack and leak. I had the fitting repaired. Ive been told that some of these pump out stations use such high pressure pumps, that the vent line cant let enough air in/ or a plugged vent line provides insufficient air intake causing the collapse. I bought a back up vent that attaches to top of tank, that opens up when to much air is being sucked out of tank to allow air in and prevent collapse. I had a neighbor who had same issue on his sear ray, and installed one of these years ago and never had it happen again. The part only cost about $60. Cheap insurance even if it has never happened before. Hopefully this solves that problem. Winter and havent used since installed.

[shrew]

Originally Posted by pirate

Just FYI I had issues with smell and found out the pump out caused the the tank to collapse. This caused the bottom hose fitting to crack and leak. I had the fitting repaired. Ive been told that some of these pump out stations use such high pressure pumps, that the vent line cant let enough air in/ or a plugged vent line provides insufficient air intake causing the collapse. I bought a back up vent that attaches to top of tank, that opens up when to much air is being sucked out of tank to allow air in and prevent collapse. I had a neighbor who had same issue on his sear ray, and installed one of these years ago and never had it happen again. The part only cost about $60. Cheap insurance even if it has never happened before. Hopefully this solves that problem. Winter and havent used since installed.

The issue isn't that there is too much suction. It is not the result of an undersized vent (design). The vent is partially blocked. This is pretty common with the Perko chrome through hull vents. There is a screen inside. They corrode over time. In fact this is pretty common with all but Bronze through hulls.

The same problem when fuel starts to burp when filling forcing you to fill very slowly with fuel, or fill and stop when you hear it gurgling.

[pirate]

Shrew, you may very well be correct. After hull out I noted a lot of dried caked wax on thru hull vent, that was left when I had hull waxed. Since I cant be certain that was issue, or if the vent is plugged somewhere else, I added the safety vent to top. I will certainly check that thru hull in a couple months when the hull gets waxed again for launch.

[MoonRiver]

I seconded the vent screen being clogged at the thru hull fitting. I had this issue 2 seasons ago. Now I clean the screen as part of my spring prep.

[pirate]

Thanks to all the replies for your feedback