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Newage PRM
Marine Transmissions - PRM500 |
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PRM500 |
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The
PRM500 marine gearbox is purpose built for
use with both pleasure craft and commercial
boats. |
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PRM500 Nominal Power Ratings |
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Ratios |
Pleasure |
Light Commercial
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Heavy Commercial
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BHP |
kW |
BHP |
kW |
BHP |
kW |
1.459:1
1.935:1 |
6.38 |
4.75 |
6.19 |
4.62 |
5.90 |
4.40 |
2.565:1
2.904:1 |
6.19 |
4.62 |
5.90 |
4.40 |
5.90 |
4.40 |
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Maximum operating speeds: 4500 rev/min intermittent, 4000 rev/min
continuous |
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Note: These
powers have been measured at the engine
flywheel. Ratings have been established to
ensure the long trouble free life of the
gearbox which should not, therefore be used
at powers in excess of those shown. |
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PRM500 -
Full Hydraulic Operation - Inline or Offset
Output Shaft |
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The PRM500 marine gearbox is
purpose built for use in
both pleasure craft and
commercial boats; its twin
countershaft design provides
separate oil-operated
multi-disc clutches (which
need no adjustment) for
ahead and astern drive
allowing full rated power to
be transmitted continuously
in either direction.
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To cater for the widest
possible variety of boats
the PRM500 is offered with a
choice of reduction
ratios,1.459:1, 1.935:1,
2.565:1 and 2.904:1. All can
provide either left-hand or
right-hand propeller
rotation in "ahead", making
the PRM500 particularly well
suited to twin engine
installations.
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The gearcase is constructed
of high grade cast iron,
internally ribbed for
rigidity and strength, and
consists of two separate
halves to facilitate
servicing, the oil pump and
hydraulic control valves
being externally mounted for
easy accessibility.
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The hydraulic operating
system functions on normal
lubricating oil of the same
viscosity as that used in
the engine, avoiding the
need to use automatic
transmission fluid, and
ensures rapid response to
movements of the operating
lever for good boat
handling. The operating
lever has a positive neutral
detent and is suitable for
use with proprietary single
lever remote control
operating systems.
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Robust and reliable, the
hydraulic system is
nevertheless provided with a
mechanical lock-up device
for added security, so that
in the unlikely event of
hydraulic failure the boat
can be brought safely back
to port. Access to this
device is via a detachable
cover located on top of the
main gearcase.
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A special feature of the
PRM500 is the direct drive
power take-off which is
available as an optional
extra; this will power a
hydraulic pump to SAE J744C
type 'B' specification, thus
providing an economical and
space efficient means of
driving on-board machinery.
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A Trolling Valve is also
offered as an optional
extra. This is
electronically operated
which allows variable speed
of the propeller to zero
whilst allowing a maximum
engine speed of up to 1200
rpm.
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PRM500 -
Service Classification Definitions -
Pleasure |
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Limited to planing hull
pleasure craft; operation at
full engine throttle should
not exceed 5% of total time,
with balance of usage at 90%
of full throttle engine
speed, or less. Maximum
operation 500 hours per
year. The selection of PRM
marine transmissions
according to this
classification for any
commercial boat, or in
sport-fishing charter boats
or in long range pleasure
cruisers, is not approved.
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PRM500 -
Service Classification Definitions - Light
Commercial |
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Planing or semi-displacement
craft used in pleasure or
commercial applications may
qualify for light commercial
rating if annual usage is
less than 1500 hours and
full throttle operation is
limited, with most operating
time at partial throttle.
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PRM500 -
Service Classification Definitions - Heavy
Commercial |
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PRM Marine Limited
recommends that all
displacement and
semi-displacement craft used
for commercial applications
should be classed as heavy
commercial duty. In vessels
of this type (including
trawlers, purse seiners,
lobster and crab boats,
tugs, ferries, offshore
supply boats etc.) the
marine gearbox is expected
to work at full governed
engine speed. The power
setting of the engine must
be known and must be within
the gearbox's permissible
heavy commercial rating.
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Important to
Note: |
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It is essential for the
engine, transmission model,
reduction ratio and
propeller size to be
correctly matched so that
the engine can attain its
rated speed appropriate to
the relevant service
classification without
labouring.
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It is also necessary to
ensure the torsional
compatibility of the
complete propulsion system
from engine through to
propeller, since
disregarding this may result
in gear noise, particularly
at low speed operation, and
may even result in damage to
the engine as well as the
transmission components.
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Trans Atlantic Diesels will
provide all possible
information and assistance
to help find solutions to
potential torsional
problems, but it is the
ultimate responsibility of
the person assembling the
drive and driven equipment
to ensure that they are
torsionally compatible.
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Back to
Newage PRM Marine Transmissions |
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