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).
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
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
least 0.3-m-thick ice is presented in Appendix B.
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.