AWO Near Miss 23-17 – Broken Anchor Chain Spline

While heaving the starboard anchor at anchorage, the anchor windlass became bogged down once the starboard anchor reached the water's edge.  The crew attempted to lower the anchor back into the water to try to re-hoist. To lower the anchor the crew had to lift the riding pawl to allow the anchor to pay back out. When the crew stopped lowering the anchor below the water's edge, the anchor started to drop in a free fall. Recognizing this, the AB operating the windlass left the controls and applied the break. As the break was being applied the mate left the rail and went to drop the riding pawl back down. By the time the anchor was secured, there was 1 shot of chain at the spill pipe, an estimated length of about 45' of chain was in the water, in the water depth that the vessel was maneuvering in, the anchor was clear of the bottom.

The captain acted immediately, maneuvering back to an anchor position where they could use the port anchor to secure the vessel. The chief engineer, assistant engineer, and mate on watch proceeded to take apart the starboard anchor windlass motor once the vessel was safely anchored and swap out the broken spline with a new part. When the old spline was removed, it was discovered that the middle was cleanly broken into two pieces.

 

Once the new spline was installed and the motor was re-assembled the crew was then able to retrieve and secure the starboard anchor in its normal stowed position.