noun, counter
boat length (racing unit); distance between boats
Used in boat racing to measure the distance between boats, where one 艇身 equals the length of one boat. Functions as both a noun and a counter.
彼の艇は2艇身の差で勝った。
His boat won by a margin of two boat lengths.
レースでは、1艇身のリードが勝敗を分けることもある。
In a race, a lead of one boat length can sometimes decide the outcome.