“Idling on one engine to avoid detection”
Shouldn’t all the engines have been off then?
The PT’s had 3 shafts: one deeper on centerline while the outboard shafts on either side were shallower. All engines had sound mufflers on them that restricted rpm’s and had to be disengaged to get full performance.
The center shaft, being deeper, did not throw as much of a tell-tale wake that could be seen by an aircraft at night. Japanese floatplanes were the primary threat to the PT’s.
As I understand it, Lt. Kennedy was operating in a sort of skirmish line. One of the boats — not his — was equipped with radar. Their outboard engines were disengaged and they were idling on the central engine to both dampen noise and not leave a detectable wake.
Kennedy was idling PT109 out of gear instead of coursing a figure 8 to stay on post. Communication to the engine room is a delayed reaction to place the screws back in gear.
The PT Boats had 3 Packard v8 engines, all unmuffled. Think about it for a second: they DID want to be under power, but those Packards were LOUD!
While I am no Kennedy fan, he and thousands of others had a LOT of difficult choices.