What is the single most important thing every crew member should remember about carbon monoxide from this incident?

A. CO is only a risk on very old boats with poorly maintained engines

B. CO has no smell, taste, or colour, so it cannot be detected by the senses alone — headache, drowsiness, and confusion near a running engine, generator, or heater should always be treated seriously and acted on immediately, not dismissed as tiredness

C. CO always has a strong smell, so anyone can tell when it is present

D. Only the skipper needs to know about CO risks, not the rest of the crew

A. Carbon monoxide (CO) poisoning from engine exhaust fumes — CO is invisible and has no smell, so headache, drowsiness, and feeling sick with no other obvious cause, especially with an engine running nearby, should always raise this possibility immediately

B. Seasickness, even though the boat is moored still in harbour and not moving

C. A normal reaction to being in a small cabin and not worth investigating

D. Simple tiredness from a long day — nothing further needs to be considered

A. Wait a few minutes to see if the headache passes on its own before doing anything

B. Turn off the engine immediately and get everyone out into fresh air on deck straight away — stopping the source and getting clean air to the casualties matters more than anything else in the first moments

C. Move the affected crew to a different part of the cabin, away from fresh air, to rest quietly

D. Open a small hatch slightly but keep the engine running, since it is needed for the battery charge