R&R WTC Ballast Tank fills when pump off

[Wax Savage]

Hi guys,

I am attempting to get my sub surface balanced. My WTC has a problem. Water is entering via the water intake and filling the ballast tank even though the R&R WTC pump is not running. This flow into the ballast tank is screwing up my ability to surface balance the sub. Effectivly, the boat is spontaneously sinking while I am trying to surface trim the boat with foam and lead weights. I have temporarily plugged the brass water inlet tube so I can continue with my balance tests.

Please help. Subfest is only a month away.

[neitosub]

It's normal that a little bit of water enters via the pump, since the system doesn't have a valve. How much water is flowing into the ballast tank per minute do you reckon?

[type7]

Yes, there is no valve so some water does enter. Since it doesn't take long to check buoyancy, have the pump pushing water out while ballasting to keep water from flowing in. Also, I have found that some water will remain in the tank so surface trim will be lower than initial height when putting the sub in the water.

[redboat219]

Looks like you already solved it using a plug.

is there still enough space inside the wtc to install a servo operated pinch valve and switches to activate the pump in lieu of the esc? like Nate's Blueback set up.