Alan, Some of us are constrained in who we can communicate with. The onus is on an individual to seek out PSUBs, you are welcome to follow up with the builder of the oil-drum sub. Efforts last year to develop standards for PSUBs so that other professional submarine communities would recognize PSUBs as members of that larger community were abandoned after realizing the liability was too great. By actively seeking out persons such as the Chinese designer, you assume some degree of liability (at least in US Courts) for their design. And finally most of us have only so much time for PSUBs, especially with a Conference coming up and having to finish a presentation. Brent’s design has the opportunity to extrude the sealing surface into the sub (not just a simple dripping leak) as it is not a captured seal. Once it starts to extrude, the rushing water will accelerate the extrusion. There is no way to stop this leak once it starts. Typical PSUBs have little reserve buoyancy so depending on the leak rate, blowing ballast (and dropping your emergency weights) may not bring you to the surface. I believe Carsten has stated that Euronaut can still make it to the surface with the diving/deco chamber flooded but his sub is in a whole different league. Most military subs are designed to be able to make it to the surface with 1 flooded compartment (at least they previously were designed this way). On modern military sub, all sealing surfaces subject to sea pressure are sealed with captured O-rings and have a backup means to seal the opening (i.e. double hatches or 2 valves, two O-rings do not count). 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 Alan James Brent, Gosh its nice to do some Brent bashing for a change. I was feeling sorry for the Chinaman. I don't think that your seal design is in the same ball park as the Seeker tragedy. Worst case scenario, you'll get some drips on your head. Noted that after all the pontification about the Chinese death trap that you were the only person in the group safety conscious enough to forward the sugestion of getting in contact him. Alan |