It was Canadian whalers, the Norwegians tell us, who first noticed that a dead whale does not bob in the waves. The carcass didn’t pitch or roll, either, and it was somehow “self-propelled” — its fins giving it forward motion and acting as stabilizers, or foils. The story still inspires Trondheim company Wavefoil, maker of scalable, retractable foils that offer ship owners and designers fuel savings and passenger comfort. In Norway, high-speed ferries, cruise ships and fishing vessels are the...
https://mfame.guru/answer-why-fishing-boat-captains-like-foils-ability-to-retract/