Water tank vent... Stopping sea water getting in

[thalassa]

I'm wary now about filling until water comes out of the breather. We have a heavy duty rigid plastic tank, it's very rigid but there is some flex to the top. The 35mm filler spigot is right next to the 18mm breather outlet. I've found that if you fill too fast a huge bubble can form in the top of the tank which cannot get out of the breather. Only realised when the cabin sole popped off the screws recently. Moral is fill slowly as I think Uncle Tom C advised in a mag article some time ago.

Apart from the internal vent being high up (and running off in the bilge), our water tank has two access ports for cleaning out. However, the round covers have only a short thread to close the ports off. They are splash proof but far from watertight. We were distracted once when filling up, and ended up with a very wet bed... Since then, I've installed a float switch in the tank, which triggers a buzzer so we know when the tank is nearly full.

 

[Danbury]

Thanks for all the input... and there was me thinking that there was a 'standard' way of doing this !

 

[alahol2]

Genius!!! I'm have the same issue, and this may just be a solution.

Will need to drill a small hole at the highest point of the pullpit railing though to let air in (my water tank's at the bow)...

You'd be much better off with a hole at the bottom. The air will still get in but any water inside will be able to drain out.

 

[Lodesman77]

Presumably because the assumption is that you will fill using a hose, and continue until you see water pouring out of the breather.

Pete

Not a valid assumption - the whole point of leading the breather pipe to a high point is that the water will never come out of the breather - it will come back out of the filler pipe first.