The Rennie Grapnel is usually used in conjunction with the Gifford. The Rennie Grapnel is built up of flat links, the fluke passes through the body and is then welded onto it. The links are joined together in sets of four in the form of a chain, successive links and flukes being at right angles to each other. Flukes can be detached for renewal when required.
It is often used with two Gifford grapnels to provide weight and hold the grapnels down. The Rennie Grapnel can be used on any type of seabed but originally designed for rocky environments.