Many captains now carry illicit firecrackers on board to throw at the whales. Some blast death metal on Bluetooth speakers. Others bash steel sticks against their hulls when orcas approach. Orcas have sunk at least three boats and damaged hundreds more. Nobody has died. Wild orcas, as far as we know, have never killed a human being. But sailors worry it’s just a matter of time, while orca biologists are anxious about captains arming themselves and taking things into their own hands.