TANKER TECHNOLOGY
ARCO: Environmental, Business Advances
Forged Through Technology
The distance between the inner and outer
hull is 10 ft. (3 m), or 50 percent greater than
required by OPA90. The ships are designed for
maximum durability, given not only the envi-
ronmental concerns, but the harsh operating
environment which they will be subjected to for
more than 30 years. For example, an addition-
al 8,000 tons of steel will be used for the
Millennium design versus comparably sized
tankers.
While the double hull is beneficial (and man-
dated under OPA 90), ARCO considers it the
last line of defense, and has incorporated the
several redundant systems to ensure the vessel
avoids trouble from the start.
Two main, slow-speed diesels will be
employed on each ship and located in com-
pletely independent engine rooms. The
engines will be fueled by independent fuel sys-
tems and can be operated, if desired, from inde-
pendent control systems. Failure to one engine
due to fire, flooding, fuel contamination or
mechanical failure will not affect the ability of
the vessel to complete its voyage.
Each engine will drive a separate, control-
lable, reversible pitch (CRP) propeller, greatly
adding to the vessel's maneuverability. The
CRP propellers can go from full-ahead thrust to
full-astern thrust in a matter of seconds, with-
out reversing the direction of the engine rota-
(Continued on page 44)
OUTBOARD PpOFIj F
When ARCO ordered two double hull tankers for the U.S. West Coast to Alaska oil trade, it sent minor tremors throughout the industry as the $166 million per ship price tag was divulged. (See MR/EN August 1997,
pg. 98). Price (high, low or just right) notwith-
standing, the new Millennium Class vessels,
which will be built at Avondale's New Orleans
facility, encompass dozens of technological
advances which are designed to keep the ships
running — efficiently and environmentally
safe — for three decades.
Meeting The Challenge
The words "the State of Washington" stir up
reactions ranging from disgust to rage in most
tanker owner circle..
The state, in an effort to protect its environ-
mentally-sensitive areas and citizens, has been
at the forefront of developing and implement-
ing regulations, over and above international
and national rules, for tankers trading in its
water. Shipowners contend that any rules and
regulations beyond what is mandated by the
IMO prove unnecessary, confusing and burden-
some — particularly in regards to the bottom
line.
ARCO, which will use the new vessels
specifically for the 2,400-mile round-trip route
from Valdez, Alask,a to Cherry Point, Wash.,
has delivered a design which has won the
endorsement and praise of Washington State
legislators.
The company — which currently owns and
operates 10 vessels with a total capacity of 9.5
million barrels — obviously has set out to
design, build, own and operate a ship which is
both economical and safe.
The Millennium class will combine double
hulls, independent engine rooms, redundant
propulsion and twin steering systems, as well
as a separate bowthruster and navigation sys-
tem.
The Design
ARCO's new 125,000-dwt Millennium
design takes advantage of the company's 80
years of experience in operating tankers, but it
is truly a collaboration of some of the world's
foremost ship designers and builders.
The new class was developed with the help
of J.J. McMullen Assoc., MCA Engineers Inc.,
SSPA Maritime Consulting AB, Herbert
Engineering Co., Glosten Associates Inc., Anna
Knutsen and Astilleros Espanoles.
Determining a size for the vessel, given its
route, was easy, considering that 125,000-dwt
is the maximum permitted by law in the Puget
Sound area.
The ship's 12 cargo tanks have a combined
capacity of just over one million barrels. The
double-hulled ship is designed to provide pro-
tection against collision and grounding. The
second skin completely envelops the cargo area
and other tanks containing fuel or lubricating
oil. ARCO has implemented the double hull
requirement with a very conservative structur-
al design philosophy.
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