water tank breather pipes

[blue-max]

 I have 3 water tanks and I can see 2 breather outlets in the cockpit. They don't seem to  work. There is a lot of back  pressure in the pipework when filling. Perhaps these pipes have collapsed or got squashed - no  idea of the pipe run. Has anyone else had this problem and the solution?

[tiger79]

The breather pipes tend to be spirally reinforced, so unlikely to squash.  They usually go up into the coaming before dropping down to the outlet.  Outlets sometimes have mesh screens; if these get blocked it could lead to the problem you're experiencing.  You should be able to follow the route of the breather pipes by delving around in lockers.

[Yngmar]

How did you test them to conclude they don't work? If the vents don't work, the tank will get under vacuum and the pump will stop being able to draw water very soon.

When filling with the hose, I always run it until the water comes out of the vent, which flushes out anything in the vent (and gives them a little bit of chlorine that I add when filling). No problems on both our tanks. You can also feel the air coming out of the vent when the water goes in. The hose runs on ours are both inspectable (bow with some gymnastics and a mirror).

[blue-max]

I have filler pipes on each side deck + another  on the foredeck. when filling the water flows out of the filler pipe onto  the deck  but is not filling the tank.
 When I fill from one side deck  and  later  open the other side deck filler a strong gust of air is released. There is no evidence of air coming out of the breather terminals in the cockpit. As a centre cockpit its hard to  work out the pipe runs for the breather pipe.

[Yngmar]

That's very odd, especially the part where filling one tank pressurizes the other! You'll have to figure out your hose runs to see what's going on. Perhaps there's some valves to move water between them?

Inspection cameras and mirrors might help, although our centre cockpit Bavaria is actually very well inspectable apart from the bow filler which runs in the peak of the bow, which is a bit awkward to stick your head in.