keeled scale

例句：

1. 1. The ship's keel is made of a special material to withstand the strong currents.
   这艘船的龙骨是用一种特殊的材料制成的，以承受强烈的水流。
2. 2. The keel of the boat is visible through the water, marking its position.
   船的龙骨在水面上可见，标示着它的位置。
3. 3. The keel of the ship was damaged during the storm, requiring immediate repairs.
   风暴期间，船的龙骨受损，需要立即修理。