Fresh water tank breather

[alahol2]

I am in the process of replacing a flexible water tank with a 'fixed' moulded tank. I will need to add a breather pipe to the setup. I am planning to run a 1/2" hose up to the cabin side and use a !/2" through hull with barb and a clam shell cover. Are there any better options than the through hull/clamshell combination?

 

[johnalison]

My boat has as original equipment a small circular fitting with a fine gauze in the aperture facing down. It is maybe an inch across and inconspicuous, but I don’t know what it is called, ther than a vent.

 

[Plum]

I am in the process of replacing a flexible water tank with a 'fixed' moulded tank. I will need to add a breather pipe to the setup. I am planning to run a 1/2" hose up to the cabin side and use a !/2" through hull with barb and a clam shell cover. Are there any better options than the through hull/clamshell combination?

Why do you need a breather? , when you fill it with water it will inflate and as you use it, it will deflate.

 

[alan_d]

Why do you need a breather? , when you fill it with water it will inflate and as you use it, it will deflate.

I think you have misinterpreted the original post. The OP has a flexible tank which he is replacing with a rigid one, hence the need for a breather.

 

[BCsailor]

Why do you need a breather? , when you fill it with water it will inflate and as you use it, it will deflate.

Because he is switching to a non-flexible tank....

We changed our breathers so that they went into the bilge. That way we we don't have to worry about sea water intrusion, spiders clogging vent screens, etc.

 

[Plum]

I think you have misinterpreted the original post. The OP has a flexible tank which he is replacing with a rigid one, hence the need for a breather.

Oops

 

[alahol2]

My boat has as original equipment a small circular fitting with a fine gauze in the aperture facing down. It is maybe an inch across and inconspicuous, but I don’t know what it is called, ther than a vent.

Yes, I've got one of those on the diesel tank but I don't think it would be big enough to cope when filling the water tank. A bigger (1/2" pipe size) one would be ideal.

We changed our breathers so that they went into the bilge. That way we we don't have to worry about sea water intrusion, spiders clogging vent screens, etc.

I had thought about that but the breather would be in the bows and I don't want overflow water running through the bilges to the stern.

 

[rogerthebodger]

On my freshwater tank I just located the 1/2" breather pipe behind the inside of the cabin liner as high as possible under the cabin roof.

No need to any external connection.

I also fitted a float switch in the top of the tank to indicate when the tank is fill of ensure the filler is below the upper level of the vent pipe for when the tank is full water will just overflow out of the deck filler

 

[alahol2]

On my freshwater tank I just located the 1/2" breather pipe behind the inside of the cabin liner as high as possible under the cabin roof.

No need to any external connection.
... when the tank is full water will just overflow out of the deck filler

That sounds like an option. I can only get the top of the breather about 6" above the filler, does the team think that would be enough to guarantee that nothing exits the breather if I leave the filler tap running for a bit too long?

 

[Boathook]

On my freshwater tank I just located the 1/2" breather pipe behind the inside of the cabin liner as high as possible under the cabin roof.

No need to any external connection.

I also fitted a float switch in the top of the tank to indicate when the tank is fill of ensure the filler is below the upper level of the vent pipe for when the tank is full water will just overflow out of the deck filler

I tried that and it overflowed via the breather !
I've fitted a hose connector to the end of the breather, the one with a 'stop lock'. Sits open until water hits it and then shuts. Needs to be in the upright position to work well. Can test it with a hose pipe at home.

Something like this -
https://www.screwfix.com/p/hozelock-12-5-15mm-single-end-female-aquastop-connector/66370

 

[Boathook]

That sounds like an option. I can only get the top of the breather about 6" above the filler, does the team think that would be enough to guarantee that nothing exits the breather if I leave the filler tap running for a bit too long?

I would not trust it. See post 10.

 

[PlanB]

We had a fixed (aluminium?) tank under the double berth in the aft cabin, with a gauze breather outlet in the transom. A few years into our ownership, something got blocked and we never did manage to find or clear it. WE just had to fill the tank really slowly to avoid loud "clunking" noises and dramatic spouts of water back through the filler.

 

[VicS]

We had a fixed (aluminium?) tank under the double berth in the aft cabin, with a gauze breather outlet in the transom. A few years into our ownership, something got blocked and we never did manage to find or clear it. WE just had to fill the tank really slowly to avoid loud "clunking" noises and dramatic spouts of water back through the filler.

But the tank must be vented to allow air in as water is drawn out.

 

[alahol2]

I would not trust it. See post 10.

Hmmm... Looks like plan A may be the safest option, perhaps with a bit of stainless gauze stuffed into the through hull.
These look like a neat enough solution.... Skin Fitting & Clam shell

 

[VicS]

Hmmm... Looks like plan A may be the safest option, perhaps with a bit of stainless gauze stuffed into the through hull.
These look like a neat enough solution.... Skin Fitting & Clam shell

Why not use a tank vent?
There are several alternatives available from Force4: straight, 90deg, 12mm 16mm.

 

[alahol2]

Why not use a tank vent?
There are several alternatives available from Force4: straight, 90deg, 12mm 16mm.

I don't know. I think I've looked at so many through hulls but couldn't find a 12mm version of a tank vent at the time. Now you've pointed me at a couple thanks.