One thing that often gets missed in dealing with safety aboard ship is the usefulness of tracking shipboard accidents and their causes, and basing safety programs on the history. Time can be wasted talking about accidents which could occur, but which are unlikely to occur.
For example, in our operation we use yard-and-stay cargo gear to move cargo. People unfamiliar with the operation see rapid speed of the gear, watch the gyrations it goes through when the ship is doing cargo transfers anchored in rough seas, and come to the conclusion that we must kill or maim a person every year. When in fact, it is vanishingly rare for anyone to get injured by the gear. Therefore, we don’t spend a lot of time talking about it.
When we track the injuries aboard our ships we find the leading cause of injuries is simply slipping on a deck. So we spend far more time trying to prevent people slipping from oil on deck, or ice, then we do preventing people from being crushed by the cargo gear. The former happens a couple of times a year. The latter has never happened in 35 years.
You can only target your safety program on reality by tracking accidents and their causes. We spend very little time talking about mooring line accidents, because no major accidents of the kind has ever happened here. But the second biggest cause of accidents here is falling down ladders and stairs. When you break down this cause even more, you find that sailors are more likely to fall down internal stairs in a berthing area than they are a rickety portable ladder in a cargo hold.
In the latter case, the person understands the danger involved and pays attention. But sailors blithely go up and own stairs at home all the time, without a thought to the danger. So they do the same aboard ship. A bad ship-roll and they fall. Hence they are more likely to get hurt on interior stairs at sea, than using a sketchy portable ladder. Therefore, our safety talks make a point about this particular hazard, which would not come to light unless someone is tracking injuries and their causes, and we all but ignore mooring line safety talks.
Again, the knowledge comes from carefully tracking accidents and their causes aboard your own vessel(s) over years, rather than resorting to general information or common wisdom.