Feature 3
Arctic LNG transportation
Vietship:
3rd floor
stand no C141
C142
at the double
Aker Arctic has undertaken the challenge of designing an
LNG carrier for Arctic conditions.
S
ince 2004, Aker Arctic has
been investigating solutions to
transporting LNG from the Siberian
Yamal Peninsula. The double acting
tanker (DAT) concept has proven to be
the most attractive, due to its icebreaking
capabilities, and the design had to comply
with Russian ice class level LU7.
The double acting Arctic LNG carrier Drawing of Aker’s concept design for an
design which Aker has produced is Arctic LNG carrier.
340m long, with a breadth of 50m, and
a deadweight of around 95,800dwt. Its
cargo capacity is 206,000m
3
and has a mode, plus good icebreaking capability
service speed of 19.5knots in open water. can be achieved with normal open water
*OOPWBUJWF
5FDIOPMPHZ

Icebreaking performance at 5knots is 1.5m propulsion power.
astern and 70cm ahead, plus the vessel also Model testing was involved to progress
GPS
8BUFS
BOE
8BTUF

has the capability to pass through ridged the design, taking place at VTT model
ice fields at a minimum speed of 1knot. test basin in Espoo, Finland. Results
8BUFS
5SFBUNFOU
GPS

Classed to LR+100A1, Liquefied Gas from tests upon DAT icebreaking LNG
Carrier, Ship Type 2G, with methane in carrier models, one with a bulbous bow,
.BSJOF
BOE
0GGTIPSF

independent tanks, type B, at a maximum and one with a sharp icebreaking bow,
pressure of 0.25kg/cm
2
and a minimum were compared, with both showing good


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TFQBSBUPS
temperature of -163°C, the carrier features icebreaking capabilities. However, the
10 deepwell pumps rated at 1600m
3
/h. icebow produced slightly better results.

$MFBO#BMMBTU
Four Wärtsilä 12V50DF engines provide The conclusions from Aker’s
gas diesel electric propulsion, with these development work suggested that an
dual fuel engines running generators. The icebreaking DAT LNG carrier is a

4FXBHF
USFBUNFOU

natural boil-off gas and forced vaporised feasible solution for Arctic trades, with
cargo gas, together with a small quantity wintertime speed reduction being kept

4FBXBUFS
EFTBMJOBUJPO
of liquid fuel, will be burnt for ignition, at an acceptable level. Ice induced speed
but the engines will mainly run on fuel decreases or downtime during loading can

8BUFS
USFBUNFOU
gas with liquid MDO fuel as back-up or as also be handled with a reasonable number
alternative fuel. This can be switched over of LNG carriers.
automatically as the need arises. However, the costs of a full build need
380
(NC)


.BSJOF
8BUFS
5FDIOPMPHZ
Its two 20MW azipods required a new to be evaluated, taking into account fuel 5IBMFOIPSTUTUS

"
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#SFNFO
size of pod unit, as the previous largest consumption and operational costs. The 1IPOF




units for heavy ice class were 13MW. calculated cost of Arctic LNG transport is
'BY




They have been dimensioned to meet the about 30% higher, compared to an open
&NBJM

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!
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icebreaking loads. Propeller diameter is water case, but LNG transport for the Kara
XXXSXPEF
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7.8m, at nominal 120rev/min. Sea currently requires 20% more vessels.
Asia
In open water mode, the vessel will Aker has a number of future projects
Pacific Maritime:
C34
operate as a normal tanker, and the podded slated for the concept, including a
propulsion will provide good open water detailed design of the propulsion system,
efficiency and easy arrangement of general optimisation of the hullform, follow-up
SeaJapan:
spaces. The vessel will operate stern ahead work with reference vessels, and the study
K-7
with pulling propellers in ice operating of ice-induced vibration effects. NA
The Naval Architect February 2008 63
NA Feb 08 - p63.indd 63 05/02/2008 15:10:45
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