Internal water tank vent ?

[TJM]

My external water tank vent is plugged - corroded and impossible to access from either inside or outside. Is there a device that I can place on the inside of the boat on top of the tank to evacuate the air so water can be plumbed in ?

We are live aboards and in the winter the Marina staff has agreed to fill our water tanks weekly. The only obstacle is the venting. We currently crack open the hose at the tank to vent it when we fill it up. I don't think the Marina staff would be that diligent in their technique. I would like to install a vent inside the boat to perform this function. Any suggestions ?

 

[psneeld]

not the greatest solution....an overfill goes into you bilge.

low chance of filling up your boat but you never know.

cant fit a vent someplace else overboard? very hard to believe that at some point you cant tap in....

 

[boathealer]

not the greatest solution....an overfill goes into you bilge.

low chance of filling up your boat but you never know.

cant fit a vent someplace else overboard? very hard to believe that at some point you cant tap in....

Maybe if you could get the end higher than the deck fill it would lessen that probability.....

 

[HeadMistress]

If you can access the vent fitting on the tank, the best solution would be to run the vent line (which prob'ly should be new hose) to a new thru-hull that's accessible.

 

[DHeckrotte]

I imagine your tanks are as inaccessible as ours. The tank fill and vent are concealed on top of the tank and the tank was enclosed in the ceiling tile.

However, you probably have the vinyl tube 'sight glass' too. Tee your new vent into the top end of it. All you have to do is get the new vent above the fill level and the marina folks will have wet feet before they fill your bilge.

 

[Comodave]

We have an 87 President 41. There are 2 tanks under the galley deck and the forward cabin deck. If I had to replace the vents, I would probably run a new vent up the outboard side of the galley and the outboard side of the dinette. My dinette is on the port side and galley to starboard. However there are many layout variations on the 41s. You will have to see where you can route new vent(s). Good luck, let us know how it goes.

 

[sdowney717]

Use a vent valve. Has a ball float that seals off when tank is full

 

[diver dave]

Use a vent valve. Has a ball float that seals off when tank is full

THat method is certainly done for millions of on the road vehicles for the fuel system, and does have merit. A couple of fairly small downsides:

The "filler person" is alerted of a full tank only when the fill overflows, since there is no "smart" sensor in the hose, and no vent to look at. Usually, not an issue to have overflow water around the deck fill, unless its freezing out.

Second, if the tank is filled with water, and the float is floating, sealing off the system, any heating of the water in the tank (by engine or environment) could cause pressure to develop in the tank system. Possible to get a tank bulge, but would depend on the amout of any trapped air, which could be very low.

 

[Irish Rambler]

From my own experience my advice would suggest you follow Peggy's. K.I.S.S.

 

[D.Duck44]

Our tanks vent inside and overflow goes into the bilge, never a problem and gives the bilge a rinse.
For fillers, I turned three through bulkhead fittings which mimic male garden hose joiners, so the fill hose just locks onto them. The centre one has an internal thread to allow a knurled knob to retain the cover.

 

[diver dave]

Is there a radio equipped bilge attendant?

 

[FF]

Remove the fill cap and drill a slanted hole in the fill pipe that will end below the deck level.


DONE.

When filling a hose stuck in the fill pipe will gurgle to allow the air in the tank to depart and when full the water gushing out the fill cap should alert you .

The small hole in the fill supply will allow water into the boat only when the fill is overflowing , the rest of the time even a 1/4 hole will vent enough even for a quality 10GPM water pump like a Head Hunter .

KISS