ship plank
A plank used in shipbuilding or on a vessel; a specialized nautical term.
船大工が板子を削って船体に合わせた。
The shipwright shaved the plank to fit the hull.
Compound of 板 (ita, 'board') and 子 (ko, diminutive suffix). The exact historical derivation is uncertain; the spelling is conventionally associated with ship planks.