Comments by "Ronald Greene" (@ronaldgreene5733) on "The History Guy: History Deserves to Be Remembered" channel.

  1. An interlocking valve arrangement and pressurized preventer locking mechanism shouldn't be that difficult to create -- it would not pressurize until the preventer key is engaged for the inner valve, which would not release again until pressure equalizes, fail safe in locked position. The outer valve to sea is mechanically unable to open until the inner valve is closed and keyed and pressure equalized with pressure at depth.
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