Final answer:
The critical safety measure for someone who has fallen overboard is to remove them from the water quickly and start CPR on stable ground. Drowning persons can't usually shout for help, and children submerged in cold water might survive even after extended periods, so resuscitation efforts should continue. Always heed 'no diving' warnings and get clear of the boat when rescuing someone.
Step-by-step explanation:
Critical Safety Measures for a Person Overboard
When a person has fallen overboard into the water, the most critical safety measure is to remove the person from the water as quickly as possible. Contrary to myth, starting CPR in water is ineffective; it should only commence once the drowning person is on stable ground. Once on land, if the person is unconscious but has an airway sealed by a muscular spasm, as often happens during drowning, administering CPR within minutes can substantially increase the chances of survival. It is essential to note, however, that the longer the brain is without oxygen, the higher the risk for brain damage, highlighting the urgency of speedy rescue and resuscitation efforts.
An additional safety measure is to be mindful of the fact that a person who is drowning is often unable to shout or signal for help, as muscular spasms prevent airway passage. Rescuers must remain vigilant and interpret any unusual behavior in the water as a potential distress signal. In cases of cold water immersion, particularly involving children, attempts at resuscitation should persist even after extended submersion due to cases of survival in these conditions.
Lastly, always obey no diving signs, as diving in shallow water can result in severe injury, and ensure to get well clear of the boat when rescuing someone to avoid getting trapped under it or hit by it.