🚤 Boats
🚤 Turn Fin
A small fin mounted near the propeller that helps a boat corner cleanly at speed instead of spinning out or "blowing over."
What it actually does
A turn fin is the blade mounted on the side of a fast boat's hull that bites the water in a turn and stops the boat sliding sideways. Without one, a high-speed boat will not turn predictably at all — it simply skates.
In practice
Position, depth and angle all matter. A fin too deep adds drag on the straights; too shallow and the boat loses grip mid-turn. Most fast boats turn better in one direction than the other because the fin is on one side only, which is why racing courses run one way.
Worth knowing
Turn fins are sharp and they take real load. Check the mounting after every hard turn or crash — a fin that folds mid-corner ends the run.