Dangerous Ice

Solas Chapter V Regulation 31 requires that the Master of any ship that meets with ‘… Dangerous Ice …’ shall report it to …

Ships in the vicinity
The appropriate authority

However we have to know what ‘Dangerous Ice’ is. If you spend most of your time cruising in warm climates it is worth reviewing this section before orals.

Types of Ice

Salt water sea ice
Fresh water sea ice
Iceberg (North and South Hemisphere)

SW sea ice

Salt water sea ice is found when air temperature is less than freezing and the sea water temperature is less than -1.3ºC. Thermal maps of the sea are useful along with taking sea water temperatures.

A tea temperature chart shows isotherms. To the north of Svalbard the sea temperature has fallen to -1.3ºC and ice is formed, becoming denser as the sea becomes shallower and closer to the land.

North Atlantic passages bring the dangers of ice accretion between November and February and of Iceberg between February and July.

North Atlantic chart shows that any direct traffic coming from Europe to New York has to pass through the iceberg area contained within 40º N and 40º W

North Hemisphere Icebergs are formed at Glacier edges and calve at a rate of 15m a day. They can take three years before they get into sea lanes off the Grand Banks.

Icebergs are are asymmetrical and are generally unstable. As they age sections fall off and they rotate until they settle in a new position. This rotation is dangerous for shipping both from the viewpoint of collision and also the tidal wave they create. — Icebergs are are asymmetrical and are generally unstable. As they age sections fall off and they rotate until they settle in a new position. This rotation is dangerous for shipping both from the viewpoint of collision and also the tidal wave they crest.

This is a 3cm radar on 1.5mile range scale. Ahead of the vessel there appears to be clear water and some brash ice or sea clutter close ahead. This can be misleading.

This is the actual scene looking forward, taken at the same moment as the previous radar screen photograph. What appears to be brash ice / sea clutter is actually the glacier front edge. This illustrates how fresh water sea ice and ice bergs absorbs radar energy making watch keeping difficult.

Ice accretion is reportable under Solas Ch V reg 31. It is a highly dangerous situation and often is too severe to be dealt with by the crew. Additional weight above causes a rise in 'G' making the vessel tender then unstable. This is compounded by list as the weight is on one side. The main remedy is to alter course to warmer climate. — Ice accretion is reportable under Solas Ch V reg 31. It is a highly dangerous situation and often is too severe to be dealt with by the crew. Additional weight above causes a rise in ‘G’ making the vessel tender then unstable. This is compounded by list as the weight is on one side. The main remedy is to alter course to warmer climate

Close all watertight doors.
Ensure the ship’s damage control equipment is ready.
Engine room warned, engines ready for immediate manoeuvre.
Proceed at a moderate speed at night.
Have the boats ready for lowering.
Post extra lookouts (crow’s nest, bow, bridge wings).
Keep a continuous radar watch.
Listen-in to Ice Patrol bulletins, obtain the latest weather and ice faxes
Radar scanner heaters on.
Winter-grade lubricants on lifeboat fails, rigging, etc.
Anti-freeze in all boat engines.
Drain the deck fire main.
Report any ice sightings or ice accretion.
Rig lifelines on deck, place sand on decks and slippery surfaces.
Maintain adequate stability