M. V. Acrtic
Speed (m / s)
Louis S. St. Laurent
b. Open propellers.
Speed (m / s)
Figure 24. Specific net thrust vs. speed at maximum shaft power, indicating propulsive perfor-
mance (after Keinonen et al. 1991).
a delivery scheduled for mid-1998.* Its displace-
ment will be 16,303 tons, and its length, beam and
maximum draft will, respectively, be 128 m, 25 m
At present, some of the largest icebreakers, such
and 9.75 m. The propulsion systems will consist of
as the Russian Yamal, are capable of operating in
22.4 MW (30,000 hp), medium-speed diesel engines
multi-year ice without any concern for possible
with acac electrical transmission to drive two
damage, often at speeds in the range of 1520 knots
fixed-pitch propellers. Model tests indicate that it
(7.710.3 m/s) (Brigham 1994). The icebreakers of
will be able to break 1.6-m-thick, level ice continu-
this class are strongly built, with a robust propul-
ously. It will have a dynamic positioning system
sion system. Because of nuclear power, their unlim-
to support oceanographic research.
ited endurance sets this class of ships apart from
The design and model testing of a new U.S. Arc-
the rest of the icebreakers in the world. Detailed
tic Research Vessel has been completed (Kristen-
information about the icebreaker Yamal by R.K.
sen et al. 1994), but it is not known at this time
Headlands of Scott Polar Institute is given in Ap-
when this research vessel will be built. This vessel
pendix A, which states that the maximum ice thick-
will support science missions in the Arctic well into
ness Yamal can penetrate while navigating is esti-
mated to be 5 m, and that Yamal has broken through
individual ridges estimated to be 9 m thick.
The contract to build an icebreaker, named Healy,
* Personal communication, A.D. Summy, Captain, U.S.
for the U.S. Coast Guard has been executed, with
Coast Guard, 1994.