ORIGINAL: gulfstreamI
You may want to try adding more lead weights to reduce this sub's excess positive bouyancy & give it a residual bouyancy thereby making it rise to the surface slowly when it's not moving.
I see in the photos that you haven't ring type weights, you can see what I say in my first photo. I needed one two or three to have the submarine correctly balanced. And the correctly depth is indicated by a front and rear red marker line on the sides of the submarine, and only the tower is out of the water. If you want I can upload the manual.
And as I see it, this sub(at least my sub) isn't hard to stay submerged
Bye
