New Flat Tank System
For LNG Containment
Approved By Lloyd's
Lloyd's Register of Shipping has
given approval to plans submitted by
Ishikawajima-Harima Heavy Indus-
tries. Co., Ltd. of Japan for a pro-
posed single - screw 125,000 - cubic -
meter LNG ship embodying separate
semimembrane IHI flat plate-type
tanks.
The ship is of double-skin con-
struction with machinery and accom-
modation fitted aft, and with six car-
go tanks. Dimensions are approxi-
mately 892 feet length by 151 feet
breadth by 97 feet depth, and the de-
sign draft is about 39 feet.
The primary barrier of the IHI
tank system employs aluminum alloy
plates, 15-25 mm thick, which have
sufficient tensile and fatigue strength
and ductility at cryogenic tempera-
tures down to minus 162° C. Thermal
contraction and expansion, and de-
flection due to liquid pressure, are
catered for by the special sectional
form of the curved edges and corners
of the tank. The secondary barrier
and insulation system consists of a
25 mm thick plywood barrier backed
up by a framework of main and sub-
joists. The spaces between the joists
are filled with phenolic foam arid pol-
yurethane foam insulation, and the
main joists are connected to the inner
hull. By this means, the static and dy-
namic pressures on the tank are trans-
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mitted through the secondary barrier
and insulation system to the main
hull of the ship.
Means of heating are provided in
the double-skin construction and in
the transverse bulkhead cofferdam so
that the temperature of the inner
deck, sides, bottom and transverse
bulkhead plating may be kept above
0° C.
This is the seventh LNG contain-
ment system approved by Lloyd's
Register. The others are the Gaz
Transport, Technigaz and Conch
Ocean (membrane-integral types),
the Conch (independent type), the
Bridgestone (semimembrane / semi-
independent type), and the Moss Ro-
senberg (spherical tanks supported
on skirts [independent type]).
Lloyd's Register has also approved
the Shell system of internal insula-
tion developed for the carriage of
LPG, in which the cargo is contained
remote from the hull by polyurethane
which is sprayed directly onto the
inner hull.
The Society is active in research
matters affecting the carriage of LNG
by sea, and has made considerable
progress in the prediction of the
forces involved in the movement of
liquids in closed tanks—a factor of
particular significance to those sys-
tems which rely on the transmission
of loads to the hull via load-bearing
insulation.
On the international level, Lloyd's
Register is collaborating with IMCO
on the production of a code of prac-
tice for LNG ships, and is simultane-
ously engaged in revising and up-
dating its own Rules for Liquefied
Gas Ships.
USCG Gives Lockheed
$54-Million Contract
For Second Icebreaker
A $54-million contract for the con-
struction of a second Coast Guard
icebreaker has been awarded Lock-
heed Shipbuilding & Construction Co.,
Seattle, Wash. The keel of the new
icebreaker, a sister to the Polar Star
to be launched the middle of this
year, will be laid next fall, with de-
livery scheduled for early 1976. These
ships, which will be the world's most
powerful icebreakers, are powered by
three gas turbines developing 60,000
hp and six diesels capable of produc-
ing an additional 18,000 hp, and hav-
ing a displacement of 11,000 tons.
New Bulk Carrier
Consortium Announced
The formation of a bulk carrier
consortium, involving associates of
Rethymnis and Kulukundis, Ltd. of
London, and Star Shipping A-S of
Bergen, Norway, has been announced
in New York by Star Shipping, Inc.,
general agents. Consisting of craned
bulk carriers of about 26,000 dead-
weight tons, the new consortium will
be marketed under the Star name and
managed by Star Shipping A-S of
Bergen. The announcement said that
the company expects to have at least
14 vessels in operation by mid-1974,
with trading principally between the
Pacific basin and the American and
European markets.
26 Maritime Reporter/Engineering News
Digital Wave Publishing