From The Annapolis Book of Seamanship
Study of the 1979 Fastnet storm and other calamitous evens reveals repeated patterns of human behavior in catastrophe that can be summarized (in my words) as the Formula for Disaster. The Formula consists of seven factors that appear time and again in major emergencies. Often only three or four of them are at play, but there are some catastrophes where all seven can be found. (These factors can be found in disasters on land as well.)
Factor 1. A rushed, ill-considered departure is first on the list because it turns up in almost every bad accident. While the demands of jobs, families, and racing schedules often dictate when we go out on the water, none of these imperatives bears any relation to the schedule that counts the most in good seamanship. That schedule is nature's cycle of tide and wind.
Factor 2. The route is dangerous because it passes through predictably risky waters.
Factor 3. The route has no alternative where the crew can "bail out." Many crews have got into serious trouble because they set courses far from intermediate harbors of refuge.
Factor 4. The crew is unprepared. Poor crew preparation can take several forms. Sailors may not be prepared for seasickness, or they come aboard exhausted. If they lack good foul-weather gear and warm clothes, they’re candidates for hypothermia. Some people do not have the basic sailing skills and experience to handle themselves and the boat. They may not have a safety harness or PFD (the skipper should have already told them to bring them.)
Factor 5. The boat is unprepared. Major damage can occur because the crew, when preparing the boat, did not have a worst-case state of mind. The results can be dangerous. To cite a few simple examples, when charts are missing, boats can't find refuge; when flashlights don't have batteries, nobody on deck can see at night; when knives are dull, lines can't be cut; when life jackets are waterlogged, they won't provide buoyancy; when the boat's batteries aren't tied down, they may capsize and leak noxious acid into the bilge and force the crew on deck.
Factor 6. The crew panics after an injury. A shipmate's injury or illness always threatens to distract the crew from good seamanship. In order to get the injured person to assistance, people may make well-meaning but poor decisions that put the boat and her whole crew at risk — like sailing toward a lee shore in a gale or abandoning ship even though the boat is floating. Even when the injury or illness is treated competently on board, crew discipline can break down.
Factor 7. Leadership is poor. Vague, weak leadership can cause low morale and lead to mistakes. Poor leadership often results from an excess of testosterone. Macho skippers unable to admit their personal limitations may lose the respect of their crews. A skipper who does not wear a life jacket or safety harness in rough weather sets a poor example, and one who does not assign a clear line of authority may cause a leadership vacuum. A good skipper knows when to defer to the judgments of more talented people and also whom to appoint in a chain of command.
To put this another way, bad things can happen when leadership is weak or confused, and when critical thinking is not employed