Vision 2009 - Rolls-Royce

NEWS
6
VISION 1-2009. Rolls-Royce
New 950AGHC gearbox
on the market
The progressive introduction of the
new Rolls-Royce reduction gearbox
range continues, and the 950AGHC
is the next size available, following
the launch of size 550 last year.
This unit has a rated input torque
of 130kNm and up to 530kNm of
output torque.
The very successful basic
single-input single-output
technology is retained, with built-in
clutch and thrust bearing and a
variety of power take-offs that
enable large shaft generators to
be driven, and electric motors to
feed power in for get-you-home
propulsion or as part of a hybrid
propulsion system.
Design changes are mainly in the
direction of increased stiffness and
more modular construction. The
attraction for customers is that
the new range both complements
and supplements the existing one.
Following an extensive analysis, the
power, torque and shaft offsets of
the new sizes correspond to current
and anticipated market demands in
terms of engine power/speed and
propeller revs for a wide variety
of offshore, merchant and fishing
vessels.
“These new gearboxes are type
numbered after the shaft offset
in millimetres, whether vertical or
horizontal to port or starboard,
in this case 950mm,” says Kristian
Tande, 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 950AGHC
the maximum reduction ratio is
6.3:1, which is greater than the
earlier series of gearboxes in this
torque rating. A secondary power
take-off can also be specified with
either vertical or horizontal offset,
whereas only vertical offset was
available before”.
Three more sizes in the new range
will be introduced in due course,
while three of the previous series
will continue, to give a torque
range from 90kNm to1,200kNm.
Most of these reduction gears will
be supplied as part of integrated
propulsion systems with shaft lines
and CP propellers. A
Two Indian sisters
Greatship (India) Ltd.
received its new vessel
Greatship Dhriti in
September last year.
Now she is working in
the Mexico Gulf on a two
year-charter. The sister
vessel was delivered
about two months later.
Greatship Dhriti is a platform
supply vessel of UT 755 LN design
from Rolls-Royce. The sister ship
Greatship Dhwani was delivered
in November 2008, and left the
shipyard to work in the North
Sea. Both vessels are DP-2, FiFi1
full service vessels capable of
supporting offshore exploration
and production globally.
With these deliveries, Greatship
owns and operates four PSVs, two
of which are contracted to work in
India, one on charter in the North
Sea, and one in Mexico. Greatship
also owns and operates two anchor
!
Name:
Greatship Dhriti
Vessel Type: UT 755 LN PSV
Yard: STX Europe
(formerly Aker Yards, Brattvaag)
Delivery: September 2008
Length and Breadth:
74m long and 16m wide
Deadweight: 3,300 tonnes
Design: Rolls-Royce
handling tug supply vessels (AHTS),
one on charter in South Africa and
one in the Middle East.
Greatship is fully owned by Great
Eastern Shipping Company. After
the delivery of the two UT 755
LN-vessels, Greatship and its
subsidiaries had an order book
of 18 vessels and one jack-up rig
under construction.
In addition to the design,
Rolls-Royce has provided the two
Indian sisters with full packages of
equipment and systems. A
Electric valve
manifold
control
Vessels need hundreds of valves
to control flow in their many pipe
systems, and valve manifolds are a
long established though low key
section of the Rolls-Royce product
range. They are supplied as part of
the UT-series design and systems
packages, and also as items of
equipment to third party pipe systems
providers. In the past, two versions
have been offered – manual operation
and pneumatic remote control.
Now, electric operation is being
introduced. The manifolds and valve
mechanism remain unchanged, they
are well proven and have a long
life. Over each valve is positioned a
complete electric actuator system,
which fits within the standard valve
footprint, including the tightly
integrated crossover manifolds. It
comprises an adaptor, the motor and
gearbox for turning the valve spindle,
the valve position sensor and the
control electronics. On top is a spindle
extension allowing manual emergency
operation if necessary.
First to be introduced is the MT50
unit covering the ND50, 80 and 100
manifolds, while a larger unit will
be produced later to fit the ND125
and ND150 manifolds. A bus system
connects the control electronics of
various valve actuators to a touch
screen or a PC, which will be used to
operate the individual valves and also
to show the location of each valve and
its position status.
The electrical actuation system can be
specified for new installations, or easily
retrofitted to vessels in service. The
older pneumatic system will, of course,
still be available. A
NEWS
7
VISION 1-2009. Rolls-Royce
C
Main internal components.
A
The vertical offset version of the new
950AGHC reduction gear.