🔍 Key Concepts

• Meaning of ice concentration in tenths and how it affects ship handling • Capabilities and limits of a reinforced (ice-strengthened) vessel versus a full icebreaker • Why higher ice concentrations drastically increase risk of besetment (getting stuck)

💭 Think About

• Think about at what point ice goes from scattered patches to almost continuous coverage. At what concentration would a ship start to lose room to maneuver? • Consider the difference between what a reinforced vessel can do alone versus conditions that normally require icebreaker assistance. • Which range seems like a practical upper limit for "generally safe" navigation, not an emergency or special-operation condition?

✅ Before You Answer

• Be clear on what "reinforced vessel" means – it is not a dedicated icebreaker. • Compare the answer choices to where ice becomes nearly solid pack (very little open water). • Ask yourself: at which of these concentrations would the ship most likely risk becoming trapped or severely slowed without specialized support?