Brent, The stainless steel Bimba cylinders are used all over the Johnson-Sealink submersibles. One side of the piston (spring-side) is open to ambient sea pressure so there is no fear of crushing. I believe in my previous posts on this subject, I specified the proper Bimba models. They have a free catalog that can be downloaded from the Web. R/Jay Resepectfully, Jay K. Jeffries Andros Is., Bahamas Save the whales, collect the whole set. From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Brent Hartwig I've been told that many pneumatic cylinders have thin walls that would be able to handle some of the depths we go to, if there is not enough pressure inside them. So in that mode they would be acting like a vacuum tank, like are subs hulls are on 1 ATM boats. So having the heavy duty SS ones like Vance mentioned would be a good plan. I'd be interested in what models of Bimba cylinders will fit are needs. B |