Water Line
Ramming Multi-year Floes (30 m)
Loose Pack (24 m)
Breaking Solid Ice (18 m)
Figure 25. New "iceraking" concept, as
proposed by Johansson et al. (1994).
0
20
40
60
80
100
120
140
160
180
200 (m)
ice sheet upward sufficiently to fracture it. The air
hull of a ship, it has now become possible to build
released from the edge of the cantilever produces
icebreakers with improved bow shapes to cope
a current to take the broken ice pieces past the 60-
with any type of ice. The developments in marine
m-wide main body of the iceraker. While moving
propulsion systems were also incorporated into the
through broken ice, the iceraker is submerged to a
icebreaking technology to obtain higher efficiency,
deeper level so that the spurs do not contact the
reliability, flexibility and maneuverability. Devel-
ice. To break a thick (8-m) multiyear ice floe, the
opment of auxiliary systems, such as heeling tanks,
iceraker is submerged even deeper and allowed
air-bubbler systems, water-deluge systems, low-
to strike the floe to split it in a single impact.
friction coatings, etc., allows an icebreaker to per-
The proposed "iceraker" represents an innova-
form effectively in ice conditions more severe than
tion that may not become a reality for a long time.
those for which they were designed.
Enormous economic driving forces must be
A description of the Russian nuclear-powered
present to encourage building this type of vessel
icebreaker Yamal is given in Appendix A. An inven-
that is such a great departure from existing ice-
tory of ships that are capable of navigating in at
breaking ships.
least 0.3-m-thick ice is presented in Appendix B.
SUMMARY
LITERATURE CITED
The current status of icebreaking technology has
Backman, A. (1994) Five years operational experi-
been presented, along with a brief history. The
ence with the Swedish icebreaker Oden. In Proceed-
improvements in bow designs to break level ice
ings, 5th International Conference on Ships and Ma-
efficiently were suggested more than a hundred
rine Structures in Cold Regions, March, Calgary,
years ago. However, those designs could not be
Alberta, Canada, p. R118.
implemented in sea-going ships because of ice-
Brigham, L.W. (1987) Emerging polar ship tech-
pushing problems. With the help of new develop-
nology--an introduction. Marine Technology Soci-
ments to reduce friction between the ice and the
ety Journal, 21(3): 35.
30
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