sea trials today good and bad

[robert lipsett]

I am using a 2 shaft 3.5 wtc in my uboat. The good news. all dry spaces remained dry. all controls were functional. The bad How long should it take to fill a ballast tank on the 3.5 wtc mine took over 4 minutes and it still was not one hundred percent full yet. it started flooding with the stick moved half way over to the side so I think throw is not a problem. the valve did not open the first few times until I touch it with a rod in the center and then it would stop and start with the control movements. Second bad thing to happen is it sunk to the bottom with empty ballast tanks. Looks like I will need to add foam to increase the buoyancy. Which foam is good for buoyancy with out getting waterlogged. Should I use blue house foam or should I use pink house foam or are the two mostly interchangeable?

[greenman407]

Blue foam and pink foam are pretty much the same. As far as the vent valve is concerned drill it out to 3/16" dia. for improved dive times and put a drop of light weight oil on it . Thatll stop it from sticking.