Ok DSDman, Years ago in my youth I was a hydraulics engineer
and I've designed power units and mobile systems o both sides of the atlantic. Someone earlier gave youths formula for sizing the pump. You have two ways you can go
1- fixed displacement
pump and then a directional valve to control the flow. This will require a suitable sized oil
tank, filter and some type of power item for the pump - can be driven by an electric motor
or a PTO(power take off) on you diesel engine
(assuming the engine has a PTO). The benefit here is that if you size the pump correctly you can add more work options as time goes by - hydraulic winches, anchor winch
etc etc etc.
2- Get a variable volume over center pump - this is a pump where you can control the amount of oil
the pump produces and you also can reverse the pumping action so the suction side becomes the pressure side and vice-versa. No valving needed, just a small tank and small filter.
Which is best? Variable volume is probably more expensive - fixed volume is simpler.
I don't know if they still exist but Cessna made some inexpensive variable volume pumps back when I was in the game
Here is the link to Lamborgini in Italy
. If you can get a part number off the motor they can help size a fixed volume pump
s.p.h.p. hydraulic external gear pumps lamborghini
Hydraulics are great and while the oil will eventually heat up - you can use a hydraulic thruster for much longer.
PM me if you need more help - but I've been out of the game
for a lot of years now