Hazards of Navigation in ICE

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When heading for ice-bound waters, one can expect following hazards:


  1. Difficulties in keeping the ship moving, speed loss, unexpected loss of speed
  2. Difficulties in maneuvering, unexpected motions of the ship, unexpected restrictions of movements
  3. Deviations from the originally planned route
  4. Ice impacts due to ship speed & ship motion
  5. Noise & vibrations increase
  6. Increased time needed for voyage, taking pilot, berthing
  7. Increased time and restrictions to rescue units arrival on accident site
  8. Difficulties in finding objects or substances (oil) that are below ice cover or under ice floe(s)
  9. Difficulties to find shoreline from radar based information
  10. Abrasive effects on ship hull painting
  11. Increased rate of rusting

Drifting ice

  1. Damage or other effects (e.g. change of location) to the aids to navigation
  2. Compressive ice: ice loads due to ice movement & pressure
  3. Ship stuck in ice/Ship movement with ice
  4. Anchoring not possible due to
  5. Movement of newly broken channel / old channel from its original location
  6. Ice accumulation on the side of the ship, on the deck

Ice blocks, ice floes

  1. Extra echoes on radar screen
  2. Ice blocks below the ship bottom
  3. Echo depth sounder may not work properly
  4. Ice block jammed in front of the propeller or between hull appendages
  5. Ice in the sea-water intake for machinery cooling system, fire main
  6. Ice in the transverse thruster tunnel
  7. Ice loads on the propeller
  8. Ice loads on the rudder and other appendages
  9. Stones from sea bottom sticking fast to ice blocks in shallow water


  1. Difficulties with visual observations
  2. Difficulties with radar based information
  3. Makes the channel more heavy to navigate
Related Post:  Summary of Ice forms

Low temperature

  1. All effects of low temperature (e.g. => -35°C in the Gulf of Finland)
  2. All effects of temperature changes and temperature differences
  3. Effects on materials: thermal strains, brittleness, thermal expansion
  4. Effects on oil viscosity: effects on fuel oil, hydraulic oil, lubricating oil
  5. Moisture condensing and/or freezing on cold surfaces
  6. Freezing of cargo, deck equipment etc.
  7. Difficulties with battery operated devices
  8. Hypothermia

Spray ice, icing:

  1. Difficulties with visual observations (frozen windows on bridge)
  2. Weight increase in the upper structures, draught increase, loss of freeboard
  3. Deteriorating of ship stability, listing
  4. Ice on outer decks and other surfaces, clogged deck drainage pipes, ice on deck equipment, frozen life saving equipment (lifeboats, davits etc.)

The hazards mentioned above could result in following damage:

  • dents and fractures due to ship-ice contact
  • ship collisions in ice
  • grounding events due to difficult ice conditions
  • ships in bad condition or inadequate ice strengthening
  • propeller damages
  • rudder damages
  • surface damages (painting),
  • main engine or other machinery malfunction

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