Did anyone mention basic first aid skills (actually some of these are at the EMT level) such as stopping perfuse bleeding, maybe setting (really immobilizing) a broken bone, immobilizing a puncture wound, packing it with gauze, first aid for severe sunburn, or other exposure (hypothermia, hyperthermia), performing CPR, neutralizing a bad jellyfish sting, removing barbs from various stinging animals, etc???
Self protection against aggressive - potentially carrying firearms - e.g. handguns, rifles, ak47s (and not just 1, but at least 1 for each crew member to fend off attackers on the open ocean with plenty of ammo and clips that are full), etc.