I'm 66. When I was young, some of the older commercial
boats still were using power takeoffs to run winches. The boats would have a shaft going to the anchor winch
and another going aft to gurdies or seiner winch
. But in those days even small diesels were heavy duty. Except for Cat or Cummings most smaller diesels today are light duty. You can only take so much power off the crank pulley without having other problems. And it isn't free power. The closer you get to peak HP the more fuel
will be used. The best way to take power off the crank is a front power takeoff in line with the crank (no side loading).
You can run an aux shaft parallel with the engine with roller bearings with a large enough diameter to handle the horse power you're going to pull off. An open shaft is dangerous. It can wrap line, clothes or people around itself with all the horse power of the engine. A lot of farmers get wrapped in PTO shafts.
If running a AC generator
is your goal, a better way is an inverter
and bigger alternator
. That's how I run w/o running an ac generator
. Another choice would be to add hydraulics.