& auxiliary machinery - Geislinger

June/July 2009 • the journal of ships' engineering systems
& auxiliary machinery
Arctic ships Tunnel thrusters Ballast water treatment

Rolls-Royce strengthens
new gearbox range
A
nother stage in the progressive roll-out
of a new Rolls-Royce reduction gearbox
range was marked by the recent release
of the 950AGHC modeL which follows the size
550 launched last year. The latest unit has a
rated input torque of 130 kNm and up to 530
kNm of output torque.
The basic single-input/single-output
configuration with built-in clutch and thrust
bearing is retained, while power take-off
options enable shaft generators to be driven.
Provision is also made for electric motors to
feed in power for emergency propulsion or
form part of a hybrid propulsion system.
Complementing and supplementing the
established range, the new series benefits from
design changes that mainly targeted increased
stiffness and a more modular construction.
Following an extensive analysis, the power,
torque and shaft offsets of the new sizes
were determined to correspond to current and
anticipated market demands in terms of engine
power/speed and propeller rpm for a wide range
of offshore, merchant and fishing tonnage.
"The new gearboxes are type-numbered
from the shaft offset in millimetres - in this
latest introduction, 950mm - whether vertical
The vertical offset version of the new Rolls­
Royce reduction gearbox
or horizontal to port or starboard," explains
Kristian Tande, Rolls-Royce technical product
manager for reduction gears.
"Large reduction ratios are inherent in the
design, allowing for all the popular medium
speed engines and permitting low efficient
propeller speeds to the extent that the hull
lines allow.
"For the new 950AGHC gearbox the
maximum reduction ratio is 6.3:1, which is
greater than the earlier series of gearboxes in
Internal components of the Rolls-Royce
950AGHC gearbox
this torque rating. A secondary PTO can also
be specified with either a vertical or horizontal
offset, whereas only a vertical offset was
available before."
Largest viscous-type damper from Geislinger
Austrian elastic coupling and torsional
vibration damper speCialist Geislinger recently
delivered its largest-ever viscous-type damper,
a Vdamp unit with an outer diameter of 1.6m
for a Korean-built two-stroke engine.
ZF extends Austal references
Transmissions based on ZF Marine's new 9000
series gearboxes are serving two 69m-Iong ropax
catamaran fast ferries delivered by Austal to the
Kingdom of Saudi Arabia. Jazan and Farasan
are powered by four MTU Series 4000 M73L
high speed engines, each developing 2,880kW
at 2,050 rpm.
The engines drive Rolls-Royce Kamewa
waterjets via ZF 9050 NR2H-type non­
reversing horizontal transmissions. Designed
and manufactured by the German specialist in
Friedrichshafen, the new 9000 series embraces
many models, including vertical offset, down­
angle and vee-drive configurations for fast craft
applications. Deep ratio variants for workboats
16 I Marine Propulsion I June/July 2009
Only 19 working days were required
between contract signature and delivery
from the company's Salzburg base, both
and a special model with the input shaft arranged
above the output shaft are also offered.
ZF 9050 NR2H parallel shaft. horizontal
transmissions are 'handed' to facilitate compact
propulsion drives with twin engines arranged
forward and aft in each hull of a catamaran.
Designed to meet Germanischer Lloyd's rules, the
system has a continuous power input capacity of
1.466 kW/rpm (for example, 3,005kW at 2,050
rpm) yet weighs only U30kg.
The recent installations extend a long
relationship between ZF Marine and AustaL
ZF transmissions having been fitted to the first
vessel built by the Western Australian yard, a
30m-Iong dive catamaran delivered in 1989.
Three more sizes will join the new range in
due course while three of the previous series
will continue in production to cover an overall
torque band from 90 kNm to 1,200 kNm. Most
of these gearboxes will be supplied as part of
integrated propulsion systems from Rolls-Royce
with matching shaftlines and CP propellers.
enginebuilder and class society DNV also
giving approvals within the same time period.
Our next issue will give more information on
the Vdamp.
Since then, Austal has built 72 vessels
equipped with 168 ZF transmissions, compriSing
catamarans, monohulls and trimarans ranging
in length from 20m to ll3m, and with speeds
from 14 knots to 43 knots. These have been
delivered to commercial, defence and private
customers in 20 countries.
Currently building or on order at Austal an
another 15 vessels specified with a total of 37 ZF
Marine transmissions, one of which will be thr
200th such system from the German supplier
The orders include four ZF 60000 NR2H-typr
gearboxes for installation in the first of the m
Navy's I03m-Iong Joint High Speed Vessel clas:
contracted at the Austal USA yard. MP
www.mpropulsion.con