noun
gangplank; gangway board
A board used as a temporary bridge between a ship and a pier, or between two vessels.
船員が渡り板をかけて、乗客が岸に降りられるようにした。
The crew set up a gangplank so the passengers could disembark onto the shore.
渡り板が滑りやすくなっていたので、注意して歩いた。
The gangplank had become slippery, so I walked carefully.
タラップ is a more general term for a gangway or accommodation ladder, often used for aircraft or ships, while 渡り板 specifically refers to a simple board used as a bridge.
Compound of 渡り (wataru, 'to cross') + 板 (ita, 'board').