Working Ballast Tank and Pump System

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The ballast tank system worked perfect. I set it up  with two bilge pumps, an in and out pump, and 12v power supply. It takes a total of 2 to 3 minutes to fill or empty the 12 gallon tank. I also made the pumps work with the radio, I can operate the pumps while she’s on her way or with an external power source. This option proved to be very cool and very useful. It's a real simple system and here is how I made it.  

The tank itself is literally the entire cargo hold pretty much to scale, and water tight for the forward and aft compartments. As the water is pumped in threw the bottom, air from inside the tank bleeds out threw the spar deck drain holes. These holes run from the scale location on the outside of the hull, to the upper most part of the inner ballast tank. NOTE: For my model the ballast tank was to small. Use one inch foam sides to increase the tank volume. 14 to 15 gallons of water are needed for this model.

The in pump sits in the original tray with the intake slots closed off and has a large hole on the bottom of the hull, A flapper valve on the pump exit pipe allows water to enter the tank. When the pump is shut off the flapper closes and keeps the water from siphoning back threw the pump.

The out pump works well but was a little harder to setup. The pump simply sits in the bottom of the hull in the original tray, but the valve is complicated. The pump moves the water in the same direction the water naturally wants to flow out from the tank, so a simple flapper valve will not work. I had to make a spring loaded valve strong enough to keep water from naturally flowing out, but weak enough when the pump engages to allow water to be pump out. This valve I can up with worked great.

The valve itself was made from brass stock found at any hobby shop and one light spring found at any hardware store. The working part is simply a tube slid inside another with a cap on the end. When the pump is turned on the pressure forces the inner pipe down and the water exits through slots cut in the side of the pipe. When he pumps is turned off the spring closes the valve shut.