On the way down the ship sails through the Southern Ocean heading South. The further South one
goes the colder it gets. One of the reasons it gets colder is that the ship starts to encounter
icebergs.
They come in relatively small sizes (about twice the size of the ship).
They also come in medium sizes.
And in rather large sizes. These two are showing signs of breaking up and probably turning over.
They also come in -
VERY LARGE SIZES
One really does not want to get too close to icebergs this big. It is on the horizon and is
probably 40 kilometres across. Some of the samller icebergs above probably formed by large ones
such as this breaking up.
Further south still the sea is covered in pack ice. This is sections of frozen sea which have broken
off the main areas of frozen ocean and drifted north.
It can be very pretty to photograph. You may also note that the sea is now almost completely
calm. This is of great interest to an indifferent sailor. It was of some interest to the ship's
captain as well, which is one of the reasons the voyage route (see the map) shows us going straight
south instead of directly to Casey.
The area between the bits of solid ice are not open water. The sea is covered in a sort of slush which
is the sea itself beginning to freeze. It would not be very comfortable in that water
without protective clothing. (Even then a killer whale might decide to eat you!)
Finally the ship encountered the real thing. Frozen sea.
This is when a icebreaker is a good idea. The sea ice is usually not completely solid at this time of year
(the southern summer) buthas broken away from the land and drifted north, mostly breaking up as it does
so. If this does not happen (and just occasionally the breakout does fail) access to stations on
the mainland of Antarctica is very difficult. The ship must stay at the northern edge of the "fast ice"
as it is known and the supplies and people need to be ferried to land.
Actually, to be perfectly accurate, the Thala Dan is classed as an "ice strengthened ship" rather than
an ice-breaker.
It is strong enough to crunch into the ice to smash a path forward, or even ride up
onto it to try to break it with its weight. A true icebreaker has a forward mounted propeller
which is positioned under the ice
when the bow of the ship is resting on top of it. Sucking water out from under the ice makes it
that much easier to break.
