I have a new to me C30 that has two fresh water tanks. One is below the starboard settee and is filled by a deck fitting just above it. The other is amidships below the seat along the port bulkhead. This tank appears to be filled by overflow into the first tank. The problem I have is air gets trapped in this tank and it swells as it fills. I can only access the top, which has no protrusions and the port side which has I think there should be some venting on it. Is this a common setup and what do you do to fill both tanks?
Fresh Water Tank Vented?
- Thread starter Forrest15112
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Forrest,
Water seeks it's own level, so both tanks being connected via hose, will try to reach the same level.
The problem here is that the forward tank is higher. This causes the lower rear tank to overfill, trying to match the level of the forward tank.
I had this problem, but on my '80 C30, the rear tank did not have it's own vent. I eventually added a vent and tied it into the vent line from the forward tank. This helps my water pump to not have to work as hard on the suction side. But this is more of a band aid fix.
A better way to go would be to not have the tanks hooked up with the existing hose running between them. Rather, run a new longer hose from the first tank but bypass the connection to the rear tank. On the outlet side downstream of the rear tank is where you want to tie the new hose into the line that runs to the water pump. This way the tanks should be better isolated and each should drain as required by demand.
Note: to make sure the water doesn't seep back into the rear tank trying to equalize, put an inline flapper type (not spring) check valve before the tie in.
This is one small project that's STILL on my "to do list".
CR
Water seeks it's own level, so both tanks being connected via hose, will try to reach the same level.
The problem here is that the forward tank is higher. This causes the lower rear tank to overfill, trying to match the level of the forward tank.
I had this problem, but on my '80 C30, the rear tank did not have it's own vent. I eventually added a vent and tied it into the vent line from the forward tank. This helps my water pump to not have to work as hard on the suction side. But this is more of a band aid fix.
A better way to go would be to not have the tanks hooked up with the existing hose running between them. Rather, run a new longer hose from the first tank but bypass the connection to the rear tank. On the outlet side downstream of the rear tank is where you want to tie the new hose into the line that runs to the water pump. This way the tanks should be better isolated and each should drain as required by demand.
Note: to make sure the water doesn't seep back into the rear tank trying to equalize, put an inline flapper type (not spring) check valve before the tie in.
This is one small project that's STILL on my "to do list".
CR
My 1986 C30 had the two tanks with separate fills on deck. Each had a vent in the life line stanchion and the larger tank under the V berth drained into the starboard tank. We never had problems with this setup. I would check to make certain the vents are open.
Gary
Gary
Thanks for the suggestions, year is '78. and only the one deck filler. I asked the previous owner about it and he verified it was just the one filler. They're really about at the same level too. I have the U shaped dinette and the second one is under the seat on the forward side. Anyway, the hose between the two seems a little inefficient for filling. I'll definitely be looking into another method.
On our '84, the main water tank is below the starboard settee. Below the "midship port" settee is the black water holding tank that the head pumps into.
Our secondary water tank is below the forward vee berth and there is a water system hose between the two water tanks that equalizes the tank levels if I open the isolation valves.
Rob
Our secondary water tank is below the forward vee berth and there is a water system hose between the two water tanks that equalizes the tank levels if I open the isolation valves.
Rob
tank venting
Hi Forrest, I have a 1985 Cat 30. I had the same problem. When filling the two tanks the midships one would bloat (as Larry the Cable Guy would say) like a tick on Dracula. Mine has a vent tube which goes up from the starboard tank and is connected to the bottom of the first stanchion aft of my water fills. In mine access is through the sliding plastic door in the small storage area above the hanging locker. I took off the hose clamp at the base of the stanchion and stuck a small dowel in it. It was plugged with debris. Works fine now. No swollen tank. Tom
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