Disney Nautilus - 1:77 Scale

[Johnny Depth]

This ought to be small enough if you want a solenoid. Servo pinch valves also work very well, and cheap to implement.


Regarding the strength of the tank, if you're making it sealed, the endcaps need to be fixed very stoutly. If I assume your tank is 3" diameter, with a 50% filling of the tank pressure will be one atmosphere (14.71psi) which on the endcaps alone will be equal to a tad over 200 pounds trying to push them apart- not insubstantial.

Thank you Subculture. I will follow up on that solenoid.

My ballast tank walls are 1/4" thick and made of epoxy using the casting technique I described earlier. They must be pretty strong because I fill the tank to about 85% to 90% to submerge. In testing I've filled the tank to about 95% thanks to that amazing little water pump. The epoxy shrinks as it cures and I think that might contribute to its strength. I figured the pump would leak first.

[Johnny Depth]

6v air water solenoid valve https://www.aliexpress.com/item/3256805059668113.html

Thank you Redboat219. That looks promising. I'll order one and test it out.