That hook knife is no doubt effective, but unless your prop is very close to the stern/surface I think it unlikely you'd be able to use it to completely remove a tightly wrapped line without getting in the water and diving. At that point any sharp serrated rigging knife will do.

In my case the prop is at least 4 or 5 feet forward of the stern, and 2-3 feet deep, so I use a line cutter on the shaft. If the line cutter failed to work my preferred strategy is cutting the line, and sailing. Once the line is cut I might try slow speed motoring and/or reverse until no vibrations could be felt, but assuming some wraps remain I would prefer to sail until I could anchor in protected water and don the snorkel to check the situation. I don't feel good about leaving lost traps on the bottom, and don't like it when the line cutter has to do its job, but prefer it to damaged drive components or putting myself in danger in the water.

If the line cutter on the shaft isn't effective, I have a Grab n Go hook that is rarely used, but it can be attached to a boat hook pole and used to snag the offending trap line and bring it to deck level where it would be cut. (If conditions allow, I would tie a spare fender to the trap line so the lobsters trapped below won't be wasted. Most marinas and yacht clubs have a place where stray fenders that have been found floating free are accumulated, and you can "claim" a small one to carry for this purpose.)

BTW my Grab n Go hook is spliced to the opposite end of my anchor snubber from the chain hook.