Efficiency Reliability and Performance
PRM marine transmissions have established a world-wide reputation for quality,
reliability and in-service performance, making them the ideal choice for pleasure,
workboat and fishing vessel applications.
All PRM hydraulically operated gearboxes feature a twin countershaft design, which
enables full rated power to be transmitted in ahead or astern, with either left or right
hand propellers.
PRM80 and 120 are mechanically actuated with adjustment-free cone clutches.
When correctly matched to engine and propeller, every PRM unit will provide
trouble-free operation for many years.
All parts are designed for maximum reliability over an extended service life
In addition, running gear components are carefully specified and machined to the
highest quality standards to ensure quiet and smooth operation.
Installation Flexibility
Purpose-designed for marine use, all standard version PRM gearboxes have output shafts
vertically offset from the crankshaft centreline. However, to cater for the installation
demands of the widest range of hulls, both the PRM260 and PRM750 are available with an in-line configuration, while down
angle options are offered on the PRM750 (8°) and PRM1000 (10°), excluding 4:1 ratio versions.
PRM80, PRM120 and PRM150
units are suitable for use with left-hand (anti-clockwise) rotating engines only. In
standard form, all other PRM gearboxes are built for use with left-hand rotating engines,
but can be converted simply to accommodate right-hand (clockwise) rotation engines by
turning the oil pump through 180°.
A wide range of mounting adapters is available to enable PRM gearboxes to be fitted to
most popular engine models. An engine/gearbox matching chart is available on
request.
Easy Operation
Hydraulically operated, adjustment-free multi-disc clutches ensure rapid response to
operation of the control lever for good boat handling and manoeuvrability. All models are
designed for use with proprietary single lever remote control operation systems.
Operational Convenience
Gear ratios and performance for all models except PRM80
& PRM120 are identical in both left and right hand propeller
configuration, making PRM units ideal choice for twin engine installations.
Propellers can be trailed indefinitely - for example, when sailing, under tow, or in
multi-engine installations where one or more engines is shut down.
All PRM gearbox units are designed for operation with normal engine specification
lubricant - eliminating the need for special purpose automatic transmission fluid.
Safety
Built for reliability and durability, PRM hydraulic gearboxes are equipped with a
"get you home" mechanical lock-up device. This additional safety feature
maintains the operating clutches in engagement so that the vessel can be brought
safely back to port in the unlikely event of hydraulic failure.
A safety start switch is also available as an option on all hydraulic models. This
prevents the engine from being started unless the gearbox is in neutral - eliminating the
risk of inadvertent damage due to uncontrolled boat movement on start-up.
Product Support
A world-wide network of distributors and authorised agents provides comprehensive
after-sales support for all PRM marine gearboxes users, including servicing facilities and
replacement parts availability. Copies of our current UK and overseas distributor lists
are available on request.
Servicing
All PRM marine gearboxes allow easy access to major components. In addition, service
items such as oil pumps and hydraulic control valves are conveniently mounted externally.
Gearboxes feature a split gearcase configuration to simplify major overhaul
operations.
Routine maintenance is limited to verifying operating temperatures and pressures, checking
oil levels and the occasional inspection of seals for leaks.
Optional Equipment
A range of clutched and direct drive power take-offs is available with SAE housings to
power on board equipment such as pumps and winches.
The PRM trolling valve is also available as optional equipment on PRM260, 500, 750,
1000 and 1500 models, enabling propeller speeds to be varied from 1200 rev/min down to
zero. This electronically-operated unit is fully inter-changeable with the standard
control value and can be retrofitted in service.
