One task from the Soviet cartoon "Stepa the sailor" (1955)
https://yandex.ru/video/preview/12455394379947604321





From Wikipedia
"Knot" is an independent unit of speed. To say "the ship is moving at a speed of 36 knots per hour" is wrong. The fallacy of such an expression is illustrated in the story of L. S. Sobolev "The Flying Dutchman":
- Tell me, captain, what is our speed? - Raising his glasses from his notebook, the guest asked again.

Guzhevoi had already opened his mouth to answer with his usual witticism that there were six knots an hour - in the first, and in the second they didn’t pull even three, but Piichik warned him:

- As much as it should be: full speed, twelve knots.

— Leonid Sergeevich Sobolev. The stories of the captain of the 2nd rank V. L. Kirdyaga, heard from him during the "Great Seat"