King's Quest 5's copy protection (floppy version only) was enforced with a requirement to use a magic wand to cast a "spell" at various points in the game, where the "spell" is a series of letters that the player matches to symbols in the printed manual. Launching the boat was one of the points in the game where this was required.
https://kingsquest.fandom.com/wiki/Crispin%27s_wand#Behind_t...