If the vessel is completely halted by pack ice, it is best to
keep the rudder amidships, and the propellers turning at slow
speed. The wash of the propellers will help to clear ice away
from the stern, making it possible to back down safely. When
the vessel is stuck fast, an attempt first should be made to free the
vessel by going full speed astern. If this maneuver proves
ineffective, it may be possible to get the vessel’s stern to move
slightly, thereby causing the bow to shift, by quickly shifting the
rudder from one side to the other while going full speed ahead.
Another attempt at going astern might then free the vessel. The
vessel may also be freed by either transferring water from ballast
tanks, causing the vessel to list, or by alternately flooding and
emptying the fore and aft tanks. A heavy weight swung out on
the cargo boom might give the vessel enough list to break free.
If all these methods fail, the utilization of deadmen (2– to
4–meter lengths of timber buried in holes out in the ice and to
which a vessel is moored) and ice anchors (a stockless, single
fluked hook embedded in the ice) may be helpful. With a
deadman or ice anchors attached to the ice astern, the vessel may
be warped off the ice by winching while the engines are going
full astern. If all the foregoing methods fail, explosives placed in
holes cut nearly to the bottom of the ice approximately 10 to 12
meters off the beam of the vessel and detonated while the
engines are working full astern might succeed in freeing the
vessel. A vessel may also be sawed out of the ice if the air
temperature is above the freezing point of seawater.
When a vessel becomes so closely surrounded