| 摘要 |
<p>In the placement of an anchor in the sea bed for mooring of a vessel a chaser in the form of a loop or hook is attached to a service line and the chaser is positioned on the anchor to support the anchor. A service vessel with the service line secured thereto pulls the anchor and anchor chain from the parent vessel to be moored and simultaneously lowers the anchor to the sea bed via the service line. The anchor is subsequently set in the sea bed for mooring and the chaser can then be removed from the anchor chain or returned up the chain to the moored vessel. To retrieve the anchor, the chaser is run down the anchor chain until it engages the anchor, and the service vessel then pulls the anchor from the sea bed by means of the service line and takes the anchor aboard. The anchor is then returned to the parent vessel. The present invention provides a chaser wherein the chain engaging surface of the chaser is defined by an arc of radius R not less than twice the chain diameter (D) with the longest chord contained by the arc of length not less than 2.9D. Additionally the chaser includes burial surfaces to produce burial forces transverse to the direction of sliding of the chaser. This arrangement facilitates movement of the chaser along the anchor chain when in the sea bed, and also reduces wear on the chaser caused by rubbing on the chain.</p> |
