Originally Posted by
air pig
Even if their special forces were on board they would not have the gases either mixtures or quantity to ascend from that depth (75m) on board allowing for decompression stops required to eliminate Nitrogen from the bloodstream. Read an autobiography from and ex SBS man, they used Oxygen for very shallow operations otherwise air for normal operations. If they had to approach a target unless a beach/installation recce they would surface and go in with canoes.
Even if the divers escaped, unless there was someone on the surface, what would they do then?
Unless this boat is found soon then I suspect that the outcome will be tragedy for all concerned.
They could ascend from 75m on open-circuit air, but it would be dangerous. The pp02 would be about 1.8 which is at high end of tolerance, but they would only be subject to high levels for a short period during initial ascent. They would not need any decompression stops as they would only be at 75m for a minute or two before leaving the water-lock. They could ascend with some form of collapsible or inflatable boat. I should disclose that I am an experienced technical diver, certified down to 90m on trimix open-circuit, and 80m on rebreathers.
Our SBS use Divex rebreathers with oxygen for shallow operations (<6m) and nitrox for down to about 24m. The RN FDU clearance divers use Divex rebreathers down to 80m using helium as diluent.