Jeff Liebermann wrote:
"---calibrating a pressure gauge to 10,000 PSI when the coupling line
split sending a fine spray of pressurized oil past my face."

I had a similar experience but at about 1/10 the pressure. It was
exciting nonetheless.

I was on watch in the engine room of an LSM in the middle of the Pacific
during WW-2 and we were cruising at our usual 10 or 12 knots but alone,
that is not in a convoy.

We were equipped with (2) 1800 HP 10-cyl opposed piston Fairbanks Morse
engines. To reverse an engine it is stopped then restarted with reversed
rotation. This is accomplished by shifting the position of the camshaft
within the engine with the engine controller. There is an automatically
operated electric engine brake which clamps the engine shaft to stop its
rotation during its rotation change. It has an enormous solenoid which
holds the brake off while the engine is running but this can be defeated
with a mechanical stop and a switch to save solenoid power if direction
changes are unlikely. That`s how we were running to conserve power
unescorted at sea.

Suddenly the annunciator in front of me jinggled and ordered "Full Speed
Astern". Without switching shaft brake power back on I complied.
Suddenly the engine room was full of diesel oil mist, water mist, and
smoke. I couldn`t imagine what had happened, but the engine started
fine, thank you. in the reverse direction but I couldn`t see my hand in
front of my face. After awhile, it dawned on me what had happened.
Compresson pressure had fedback into the air compressor system blowing
its pressure relief valve and filling the engine room with water from
the compressor tank and diesel fuel from the engine cylinders. It was a
mess but the exhaust air curculation soon cleared the atmosphere and no
harm was done. Never again did I forget to enable the shaft brake before
reversing engine directions. I was promoted to MoMM 3rd class and put in
charge of my watch. My battle station was gun loader on the 40mm
anti-aircraft guns.

Best regards, Richard Harrison, KB5WZI