Chasers and grapnels are used to recover the anchors and mooring lines from the seabed when the anchors are deployed by the buoy and pennant.
The material of the chain chaser is not harder than the material of the wire and chain for the purpose of avoiding the damage to the chain and wire while the wear is taken by the chaser.
In order to suit different need for conventional and pre-set mooring systems, there are various shapes and sizes of chasers and grapnels.