Actually it was Radar Directed gunfire, which negated the darkness "stealth" approach. They could be hit before their torpedos were within effective range.

Other problems were along the lines of what you said. Water-logged hulls needed to be pulled out of water for drying out periods and barnacle cleanings. As well replacement parts for engines with too many hours on them were rare/unheard of.
All this reduced speeds so that they could actually be run down by destroyers.
Old PT drinking song...
"Some PTs do 70 knots, some do 69, if we get ours to run at all, we think we're doing fine."
All 45 squadrons were sold off at the end of WW2.
They were everywhere and provided an interum naval presence after Pearl.

Close enough...Your go !

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