Polar Waters

Question 1

Sea ice characteristics

Answer 1

Ice Age -New, 1st Year, Multi Year
Ice type - Grease, Nilas, 1st Year, Multi Year
Concentration - 10ths
Thickness - Metres
Floe size -Small, Medium, Large
Snow - Centimetres

Question 2

Antartic specific conditions

Answer 2

• Antarctic Coastal Current – Westward.
• Antarctic Circumpolar Current - Eastward.
• Winds from the North/East will close ice and make conditions difficult.
• Westerly/Southerly winds opposing the coastal
  current ‘release’ sea ice.
• Low pressure systems are common and responsible for driving dynamic wind changes.
• Wind is most responsible for sea ice shift.
• Icebergs can move with current opposed to ice.

Question 3

Ice Accretion

Answer 3

Icing on vessels can result from:
- Fog.
- Freing rain / Drizzle.
- Wet snow.
- Freezing spray and wave wash.

• Superstructure icing, freezing spray is the most
  common and most severe cause of ice accretion.
• Occurs when the air temperature falls below the freezing temperature of seawater and when sea surface temperatures are
  below 6°C.
• Ice accretion rates from freezing spray can exceed 2 centimetres per hour and ice build-up of over 25 centimetres.
• As a general rule, freezing spray will not be a problem once the ice cover exceeds 6/10 concentration.

Question 4

Equip limitations

Answer 4

• Hazards associated with limited terrestrial navigational aids in polar regions.
• Understand and recognize high latitude errors on compasses.
• Identify limitations in discrimination of radar targets and ice features in ice-clutter.
• Limitations of electronic positioning systems at high latitude.
• Limitations in nautical charts and pilot descriptions.
• Limitations in communication systems.

Question 5

Operate and manoeuvre in ice

Answer 5

• Preparation and risk assessment before approaching ice, including
  presence of icebergs, wind, darkness, swell, fog and pressure ice.
• Communications with an icebreaker, other vessels in the area and with Rescue Coordination Centres.
• Conditions for the safe entry and exit to and from ice or open water, such as leads or cracks, avoiding icebergs and dangerous ice conditions and maintaining safe distance to icebergs.
• Ice ramming procedures including double and single
  ramming passage.
• Bridge team management due to environmental
  conditions, vessel equipment and ice class.
• Presentations of various ice conditions on radar.
• Convoy terminology, communications, procedures.
• Avoiding, freeing from and consequences of besetment.
• Towing and rescue in ice.
• Ship handling and risks in various ice concentration.
• Different type of propulsion and rudder systems, including limitations to avoid damage when operating in ice.

Question 6

Preparations before entering ice

Answer 6

• Heating systems – warm blown air may not be sufficient for prolonged exposure to sub-
  zero temperatures.
• Bridge window de-icing systems – functionality check well in advance to ensure all working.
• Engine intakes – it may require that the engine intakes are heated to prevent the cooling water from freezing and over-heating the main engines.
• Searchlights – operable from inside the ship, spares available – especially lamps.
• Sand/grit and other de-icing equipment available on board, including shovels and pick-axes.
• Check the sources of information – company instructions, the references at the start of this section, sources of Met information.
• Cargo care – special heating requirements.
• PPE – Artic gear, Thermal undergarments, thermal over garments, boots, socks gloves hats.
• Skin care.
• Food – cold weather operations will require more calories, possibly as much as three
  times the normal intake.

Question 7

3 ship handling rules in ice

Answer 7

• Do not enter if ice is under pressure, hummocking or rafting where the ice rides up over itself.
• Where possible, enter the ice field from leeward, where the ice is less compact.
• If possible, enter the ice in a bight, where the sea surge is less.
• Enter the ice at slow speed, at right angles to the ice edge. Once you are in the ice, speed can be slowly increased. It is important now to maintain headway and control of the ship.

The three ship-handling rules in ice:
1. Keep moving even if very slowly.
2. Try to work with the ice movement not against it.
3. Excessive speed will lead to damage to the hull by ice.