Hmm. The pressure inside a Merlin engine is about 1410 psi (about 88 atmospheres) and the temperatures inside the engine reach 2200 C. The turbopumps in the e

Hmm. The pressure inside a Merlin engine is about 1410 psi (about 88 atmospheres) and the temperatures inside the engine reach 2200 C. The turbopumps in the engine spin at about 3600 rpm and produce about 10,000 horsepower, which is just used to pump fuel into the main combustion chamber. Each Merlin engine produces about 200,000 pounds of thrust and is still reusable. Just starting a rocket engine is a complicated dance that can easily turn out badly if not handled with extreme precision. Sorry, but I don't think there is any way one can equate the complexity of a diving bell with that of a rocket.