An analysis of 18 major maritime incidents reveals that only 17.8 percent of the women survived versus 34.5 percent of the men. Does that mean that chivalry is dead? The Daily Mail certainly seems to think so.
It's not quite that simple, though gender is certainly playing a role:
Savage affirmed that given the Lusitania was under water in just 17 minutes, a stark contrast with the two-and-a-half hours it took to floor the Titanic, that passengers instinct won out as they raced for the lifeboats.That's part of the discrepancy: if you are responsible for one or more small people, you're going to be much slower to get to the lifeboats
Those that managed to swim to them were rescued, increasing the chances of men surviving as many women were responsible for their children.
Indeed, getting to a lifeboat is going to be the dominant discriminator of survival in nearly any maritime disaster. Except for the tropical seas, being immersed in sea water for half an hour or so without an immersion suit is going to ensure that hypothermia nails you. Being able to climb from the water onto debris will depend on upper body strength, where men are at a distinct advantage.
I would be very interested to see results like these grouped in ranges of sea temperature; I would expect that you'd see a sharp up-tick in female survival rates as immersion became more survivable and swimming survivors were able to swim to and climb aboard life rafts or debris. It would also be interesting to see cases where very few lifeboats were present - the greater percentage of body fat in the average woman vs average man should keep them alive longer in the water, although I wonder if it would make much difference given that help probably wouldn't arrive within half an hour in many incidents.
As an example of a modern sinking without lifeboats in a cold sea, the Herald of Free Enterprise capsize at Zeebrugge makes for interesting analysis. It capsized 90 seconds after leaving harbour, making swimming a feasible escape strategy (if thrown into the water - half the ship was still above water after the 90 degree capsize). 150 of the 450 passengers and 38 of the 80 crew died; I have not been able to find a gender or age breakdown of these numbers, and it would be very interesting to find one.
It's notable that in this accident no lifeboats were deployed - only lifejackets were used. Collections of lifejackets bobbing to the surface formed impromptu liferafts. Most fatalities were people trapped in the ship and either drowned or killed by hypothermia in 3 degree C water. The accident investigation notes that the difficulties in climbing out of submerging parts of the ship were significant, since climbing ability is again generally greater in men than women, and greater in younger people than older.
The gritty details of the incident are covered in the Department of Transport report (4.5Mb PDF).