[PSUBS-MAILIST] ballast tank

[hank pronk via Personal_Submersibles]

I mounted the first new ballast tank yesterday, I am using water softener tanks.  The tanks are real cheap and best of all, very light.   The tanks are approx. 20 imperial gallons each  12 in dia and 48 in long with hemi ends.
If I were building a K sub, I would 4 of these on, stability would improve and no burping out air. 
Hank