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Losing an anchor is serious. The ship cannot anchor safely, the equipment is expensive to replace and the object on the seabed may be a hazard to other vessels. Lost anchor and chain recovery in Nagoya is a task for divers, with careful planning around the position, the depth and the weight.
Anchors are lost when a chain parts, a shackle fails, the anchor is left behind in an emergency, or the windlass brake slips. The chain may be lost as well. A standard shackle of chain is 27.5 metres, so losing several shackles can mean over 100 metres of heavy chain on the seabed. Anchors for large ships often weigh 10 tonnes or more.
Note the position as accurately as possible, using the GPS and the radar, and record the time, the weather and the depth. If the ship can mark the spot with a buoy, do so. Tell the owner, the agent, the class society and the port authority. Many ports want to know about objects on the seabed. Give us the position and the ship's details.
The search begins at the recorded position. A Diver can search by hand using a line pattern, working in circles or lines from a marked point. Visibility in port waters is often low, so the search is slow. When the position is uncertain, a survey with sonar may be needed first, arranged through a specialist survey company. Our team coordinates this if the owner wishes.
When the anchor or chain is found, the Diver inspects its condition and attaches lifting slings or shackles. He marks the object with a buoy so the lift team can find it. For large anchors, a heavy lifting craft or the ship's own crane may be required, and the plan must include the lift weight and the sea state.
The lift is planned with the lifting vessel, the master and the supervisor. Divers stay clear of the load. The anchor is lifted slowly, checked at the surface and landed on the vessel or placed on the quay. Chains may be recovered in sections.
After recovery, the anchor and chain should be inspected for damage and cause of failure. The shackle, the kenter shackle and the swivel are typical weak points. The report helps with class and insurance.
We give a written report with the position, the depth, the method and the video record. If the object cannot be recovered, the report explains why and what the port needs to know.
Q1. How long is one shackle of anchor chain?
A standard shackle is 27.5 metres (15 fathoms), so losing several shackles can mean over 100 metres of chain on the seabed.
Q2. How heavy can the anchors of large ships be?
Anchors for large ships often weigh 10 tonnes or more.
Q3. What should the master record when an anchor is lost?
The position, time, depth and weather, and whether it was marked with a buoy. Inform the owner, agent, class and port authority.
Q4. How is the lost anchor found?
By a Diver search pattern from the recorded position, and if needed a sonar survey arranged through a specialist company.
