The tensioner is usually made of steel and has a ratchet mechanism that allows the user to adjust the tension in the lashing chain. It typically consists of a handle, a ratchet wheel, a pawl, and a hook that attaches to the lashing chain.
To use a marine lashing chain tensioner, the hook is attached to one end of the lashing chain, and the other end is secured to the container. The tensioner is then placed over the chain, and the handle is used to tighten the chain by turning the ratchet wheel. The pawl engages the ratchet wheel to prevent the chain from slipping back. The tension can be adjusted as needed by releasing the pawl and turning the ratchet wheel in the opposite direction.