Wet floor in aft cabin?

[Bob Quinn]

Different boat, etc, but my freshwater tank has a solid copper vent line and if you overfill through the deck fitting it just starts running out the vent.

Not pressurized in that scenario, but, check for a the vent maybe there is some issue there if it is overfull and leaking.

Thank you Brett, that makes sense, I figured there would be a vent somewhere, I think it's probably under the area I can't see working on emptying the tank now. I have an external "fresh water" hose running but so far the water level has not gone down "according to the gauge"
I'm thinking it's not actually fresh water, it may be sea water, but then why label it fresh water?
I'll give it some time, it could be pulling from a different tank or just slow, or bad gauge.....
Lot's to learn on these boats!

[brettportzer]

Surely you shouldn't have a sea water holding tank!

[Pascal]

The only way to solve a leak issue is to see if there is a pattern. Does it leak after it rains, after running the boat, when tank is being filled, when air con is on? Otherwise you can go nuts hunting it down

Is the water fresh or salt?

As to the water system keep in mind it may have been modified over the years. For instance I have heard of some owners rigging a valve to fill the tanks using the dockside water connection, back flowing into the tanks. Silly but you never know what could have been done.

I have never seen a boat with water tanks venting inside. That’s crazy. Hatteras typically used copper pipes for vents going to the hull side

Earlier 53s and their siblings have three tanks. Transom, under the VIP bed and keel tank under the master closet. Filling is done at the transom tank with water flowing into the keel tank and from there into the VIP tank. The VIP and transom tank have a vent each and you will see water coming out of the hull side when full. The keel tank doesn’t have a vent.

Personally I never connect any boat to dock water. Should you get a plumbing leak it will make a mess and possibly sink the boat. and by using tank water you are constantly refreshing the water. City water usually has some chlorine which helps keep the tanks clean.

You should check your water system by disconnecting the dock hose and use tank water. That will also tell you if the gauge is working

[Bob Quinn]

Found one leak, where the plate that connects the filler line to the tank, it appears that seal has sprung, so as I am filling via the rear water filler line, it is dribbling down the side of the tank.
I'm not sure it's the only problem but surely could be.

Trying to get the tank to drain to get the water level down a bit now.

[brettportzer]

I have never seen a boat with water tanks venting inside. That’s crazy. Hatteras typically used copper pipes for vents going to the hull side.

This is of course what I am describing.

[Pascal]

Found one leak, where the plate that connects the filler line to the tank, it appears that seal has sprung, so as I am filling via the rear water filler line, it is dribbling down the side of the tank.
I'm not sure it's the only problem but surely could be.

Trying to get the tank to drain to get the water level down a bit now.

Which tank, the transom tank? I don’t know what kind of hose Hatteras used on your boat but on the earlier boats like mine they a grey ribbed hoses which after 40/50 years turn very brittle and can crack. They used that on the aft deck drains as well which can result in interior leaked when it rains or when you wash the boat.

[SEVEN]

Another thing you might want to check is the hose leading from your shower sump in the aft to the sea chest. The hose on mine was split in four different locations. Every time I took a shower it sounded like it was pumping out but it was actually pumping right into the bilge and getting the carpet in the closet soaking wet. You might want to check that.

[Bob Quinn]

Leak fixed, here is what happened.....
At some point in the past someone upgraded/replaced the filler hose, at the same time they must have replaced the elbow between the filler hose and the top of the tank.
While I don't know what the original looked like, it was probably a low profile special elbow as it had to fit in a tight space between the tank and the plywood under the mattress.

So this new elbow that was installed was taller, and sits up about 1/8 or 3/16 of an inch above the top of the plywood (a big square hole appears to have been cut to allow for the access needed for the upgrade/replacement) So a 1/8 aluminum plate was screwed down over the elbow but still this all sticks up such that with the mattress in place any weight on the mattress is pressing on the elbow. It appears this caused the seam at the near edge of the tank to start to crack.

I jb-welded the leaking area and beat a cavity into the aluminum cover plate to allow room for the elbow and not allow the mattress to put pressure on the elbow any more.
Problem solved!

Thank you all for your help!

[boatwright]

if you are hooked to dock pressure water it can back fill thru the boat water pump and over fill the tanks. on our boat there were two valves one closed off the boat supply the other the dock supply. close off the one not being used.

[SEVEN]

I could be wrong but I believe those valves were an add-on by a previous owner. I have 7 Hatteras’s nearby and none of those have those valves. I remember doing an addition like that to an old Chris Craft of mine. But with these tanks and the possibility of them cracking or overfilling I would rather fill them the old conventional way. If you get a chance, can you take a photograph of those valves and where they’re located in your boat. Someone might want to copy it.