winches
From my years of off-roading experience, electric winches work best for Jeeps etc. Hydraulic winches (MileMarker was one manufacturer) that ran off the vehicle's power steering systems were much over-rated and tended to stall easily (a supposed 9,000lb winch acted like a 5,000lb. electric). A company called Bailey Manufacturing (same Bailey advertiser on this site???) (
www.baileynet.com) sells a 9000lb. winch without the hydraulic motor for $499 (P/N 375-010) Ph no. 1-800-800-1810. One of the reasons the motor is separate is, it depends on the pump volume and pressure input and "hydraulic horsepower" the input engine can input. Typically the HP output at the hydraulic motor is about 80-85% of the input from a gas engine spinning the hydraulic pump for example. Like electric motors, not all hydraulic motor are designed for the same purpose. Some are high-speed/low-torque, and some are high-torque/low speed. If you notice the chipper set up, the hydraulic pump spins very fast but the hydraulic motor spins at a very slow, and usable speed. This is no accident.
If you don't know what the specs are for your hydraulic motor either call the manufacturer and ask them what it is rated for, or take a chance a build something and test it and see how it works. Most winches--hydraulic or electric-- increase the torque by using gears--- either planetary, worm or spur gears. (Most 5000-8000 lb. electric winches only have HP ratings between 2-4HP)
Depending on the right hydraulic motor size, it's rated top speed and/or torque, type of end bearing construction (will it take a side or lateral load without destroying itself?) it may be possible to just install the motor in fabricated bracket and then extend the shaft to another bracket supported by a bearing--a "poor-man's winch". Then you can use that shaft extension as a "drum", or, if the "shaft" is large enough it could be used as a capstan.
Using an electric winch is also a good idea, providing you use a winch that is much overrated for the job--a 5,000 winch will pull double the amperage and burn up quicker and kill the battery quicker compared to an 8,000lb winch that is working half as hard and pulling half the amperage which on a winch this size, under full load can be 400-700 amps and more. (Note: these numbers are from my experience 10 years ago--there may have be advancements in technology and other things to consider, and are generalized, rough figures)