Water tank vent fittings and position

[Ric]

I've glassed in one of my saloon lockers to make an additional water tank. I'm now puzzling about vent, inlet and outlet fittings.

I can't vent the tank from the top because the tank fills the entire space under the bench. I thus will have to make a vent through the interior sidewall of the tank, then run a tube up as high as possible in the interior of the boat. Are there dedicated fittings to do this? Or should I just buy a normal nylon through-hull type fitting and attach tube to that?

I won't be able to fit the vent at the very top edge of the tank (see pic) so will end up with an unventable space at the top. Is there perhaps a dedicated u-vent that can be fitted lower down and vent from the top of the tank?

Sorry to make you turn your computers on their sides to see the pics but there seems no way to control picture orientation.

 

[duncan99210]

You say you can't vent the tank from the top: is that because the pipe would have an exposed run? My tank vents are all from the top of the tank and run to about the same level as the filler fitting on the hull, using a vented fitting with a gauze to prevent inspects getting into the tank. Just a straight run of 19mm hose from the fitting in the tank top to the vent. Fill until the water comes out of the filler or the vent. If the vent has to leave the side of the tank, I see no reason not to follow a similar pattern with allowing you to fill the tank to the top.
I wouldn't vent the tank inside the boat, too greater a chance of water getting out of the tube when heele or if you overfill.
Edit:
Skin fitting here http://timage.eu/site/90-fuel-tank-ventilators-and-drain-fittings

 

[VicS]

I've glassed in one of my saloon lockers to make an additional water tank. I'm now puzzling about vent, inlet and outlet fittings.



Sorry to make you turn your computers on their sides to see the pics but there seems no way to control picture orientation.

Here you go

 

[Tranona]

No reason why you cannot have both the fill and the vent coming in through the side near the top. My tank is like that. The only issue is that when the tank is full there is some water in the pipes, but it does not cause a problem. 38mm for the fill and 19mm for the vent. You can take the vent out of the topsides just under the toe rail with a shell type fitting and the filler on deck. Good information on tank design and fittings on the Tek Tanks site or in the Vetus catalogue.

 

[jwilson]

No reason why you cannot have both the fill and the vent coming in through the side near the top. My tank is like that. The only issue is that when the tank is full there is some water in the pipes, but it does not cause a problem. 38mm for the fill and 19mm for the vent. You can take the vent out of the topsides just under the toe rail with a shell type fitting and the filler on deck. Good information on tank design and fittings on the Tek Tanks site or in the Vetus catalogue.

From the photo it looks like a modernish boat, possibly a Jeanneau. Fully agree not to vent inside the boat. As you simply can't sail a modern Jeanneau lee-rail-under for any length of time an external vent at toerail height should be OK. Once found very salty water in a FW tank - the vent was actually run up 6 inches inside a deck stanchion, but the boat had been sailing really hard on her ear for some time and the stanchions had been regularly underwater! Used the race-required emergency water for once.