@Smith; I assume you're a Paramedic, Nurse Anesthetist or Physician considering you seem to have experience intubating. The near-drowning is an interesting thing to consider. I would imagine the person went overboard and you were able to retrieve them and get them back on deck to find them in respiratory/cardiac arrest. I think the likelihood of survival would be based on a few factors: (this info is for general public and not directed at you smith since you seem to have your finger on the pulse of things)
1. water temperature. As you know (but perhaps others don't) cold water survival rates are much higher than warm water, especially in younger populations, usually due to the mammalian diving reflex that slow metabolism upon dropping into cold water. This usually means longer resuscitation times to allow for warming before determining death. Some may say, "they're not dead, until they're warm and dead." Basically year round along the coast of New England would always count as cold water, and along Florida always warm water due to consistent temperatures. Soooooo fall overboard up north?!
2. laryngeal spasms. A "dry drowning" is due to laryngeal spasms, which still causes asphyxiation by submersion (the definition of drowning); water does not enter the lung. A "wet drowning" is absent of laryngeal spasms and allows water into the trachea and thus lungs. An intubation kit with suction (a meconium aspirator works like a champ to turn your ET tube into a laryngeal suction device) come in very handy here. Usually wet drownings are associated with intoxication or head injury as normal physiological responses are hindered (assuming you got them back aboard quickly).
3. Age. The younger you are the more likely you'll survive a near-drowning. Kids tolerate transient hypoxia a bit better (especially in cold water, as mentioned above).
4. salt vs fresh. This is usually only important is the person is revived after a wet-drowning. In fresh water the surfactant is washed away and causes the alveoli to collapse (atelectasis). When you ventilate with positive pressure you're actually forcing more fluid into the capillaries causing hemodilution (decreasing the concentration of your red blood cells is the key factor here). With salt water, if the person is revived, salt stays in the alveoli and (due to osmotic pressure) draws fluid out of the capillaries back into the alveoli. So a person can wind up with pulmonary edema hours after they've been revived and still have serious respiratory compromise.
5. distance to rescue. Can't do CPR or ventilate forever. Gotta get to definitive care: hospital.
Side note: usually "drowning" is considered death by asphyxiation within 24 hours of submersion, and "near drowning" is death by asphyxiation after 24 hours of submersion. So if you fell in the water and were revived and lived... it wasn't actually a "near drowning" (it would only be called that if you died the next day!).