How far high-pressure marine boilers could be pushed

What was the highest-pressure steam boiler used aboard ship?

The recalled figures are roughly 2,000 psi experimentally and up to 1,200 psi aboard warships, with sustained reliability and the exclusion of nuclear plants qualifying the comparison.

The opening distinction is between a pressure achieved experimentally and one that a ship could sustain reliably. Alex gives approximate figures of 2,000 psi for experimental machinery and 1,200 psi for service warships, with about 840-850 psi quoted for Bismarck. He is explicitly unsure how long the German plant could sustain its quoted figure and stresses differences in the behavior of individual machinery installations. A high-pressure steam jet can be lethal before the escaping vapor becomes visible as mist. Pressurized-water reactors are then raised as a separate case, and he clarifies that his answer was about conventional steam plants.