Should I be wary of hydraulic drive?
QI’m looking to buy a 2002 boat with an ARS hydraulic drive. Do you have any advice as I’ve not come across this system before?
This type of system has been in common use since the Seventies and ARS is well known in the field. The advantages are that the engine can be placed anywhere in the boat and aligned in any direction the design requires. Once the hydraulic motor is fitted, there is no further need for shaft alignment for the life of the boat so engine mount changing is easy. Propeller thrust is taken by the motor bearings not the engine mounts as is the case on many boats with gearboxes. There is less likelihood of expensive damage if the prop fouls badly because the pressure relief valve will just open rather than stopping the engine. It often allows an installation that minimises engine noise for the boaters.
There is, or should be, an oil filter that needs changing regularly, the reservoir holds far more oil than a gearbox and if a pipe fails they spray oil everywhere, so the pipes need regular inspections. As the components wear, the efficiency will be reduced so increasing fuel consumption and engine revs for the same speed.
If everything else was right about the boat, it would not be a deal breaker for me. I would give the boat an extensive test so I could assess the engine revs to boat speed to try to assess the degree of wear in the system when hot.