Singapore's search for missing anchors: How ships lose their metal and why they are a threat to seabed

SINGAPORE — An upcoming survey will scour the seabed around Singapore searching for lost anchors.

In March this year, the Maritime and Port Authority of Singapore (MPA) put up a tender for hydrographic survey services to locate and retrieve anchors lost in Singapore waters.

Responding to queries from TODAY, the authority said that an average of one incident of a lost anchor in the Port of Singapore is reported to MPA every month.

Ships may lose their anchors due to what is known as "dragging", which happens when strong winds blow and the anchored ship is dragged along with its anchor.

The hydrographic survey service would ensure that appropriate specialist resources are deployed expeditiously to survey the seabed, and mark lost anchors for subsequent removal.

“Despite the high marine traffic, such incidents remain infrequent,” said MPA.

“There have been no recorded accidents resulting directly from the loss of ships’ anchors in our anchorages. Nonetheless, the survey will help to ensure our anchorages remain safe for port users,” it added.

TODAY has sent MPA further queries on whether this survey is a one-off or something that is conducted regularly. 

WHY SHIPS LOSE THEIR ANCHORS

Captain Tan Kim Hock, the programme director of maritime studies at the Nanyang Technological University, told TODAY that ships typically lose their anchors for two main reasons: Poor anchor maintenance, or unskilled anchoring by its captain.

“We have a very strong inspection regime on board these ships,” said Captain Tan.

“It is mandatory for us to carry out certain surveys every now and then. We’ve got dry docking, so to speak, where the anchor cables, or chains, are pulled up all the way and inspected for any wear and tear.”

By design, the links in a ship anchor’s cable are very strong and tend to be “dislodge-proof”, said Captain Tan. In the event of poor maintenance, however, signs of wear and tear might be overlooked.

When that happens, the links may dislodge and the anchor may be detached.

Beyond maintenance flaws, unskilled anchoring by a ship’s captain could also lead to the vessel losing its anchor.

“When you anchor a vessel, there is a skill involved: How you position the anchor, how you drop the anchor,” said Captain Tan.

“It’s not like anybody can just go there and throw the anchor in; it needs to be a pre-planned operation.

“There is a lot of preparation work — study of the seabed, what type of seabed, how deep is the water, what is the current like, what is the wind like — then you manoeuvre (the ship) and you sort of have an action plan to approach the anchorage.”

Still, this factor of unskilled anchoring, due to inadequate knowledge of the surrounding marine environment, is less likely to occur in Singapore, said Captain Tan.

“In Singapore, it requires a Singapore pilot to come onboard to anchor your vessel,” he said.

Beyond poor anchor maintenance and unskilled anchoring, there may also be less common causes — such as when a ship’s anchors are lost in the event of an emergency. 

When a ship is moving too fast while approaching a port and risks colliding with another vessel, an emergency procedure involves letting go of the ship’s two anchors to restrain it.

In such instances, there is a chance that the ship might lose its anchors due to the sudden strain.

‘THE MOMENT YOU LOSE AN ANCHOR, YOU LOSE SEAWORTHINESS’

Captain Tan said that the occurrence of losing an anchor is not a common one — especially if proper maintenance and anchoring procedures are undertaken.

He has not lost any anchors since he started as a captain in 1978.

“An anchor is required — it is one of the components that must be on board the ship. The moment you lose an anchor, you lose seaworthiness,” he said.

Ships without an anchor will not be allowed to enter a port as it would be deemed an unsafe vessel, he added.

The authorities could exercise some flexibility, however. The country where the ship is registered could allow the vessel a grace period to continue travelling to its next destination without an anchor. But the anchor must be fixed at the next port, or the ship will not be allowed to sail further, Captain Tan said.

Ultimately, the main purpose of anchoring is to hold a vessel in position and keep it stationary, said Captain Tan. When its anchor is lost, the ship would risk drifting and potentially colliding with another vessel.

WHO SHOULD THE ONUS OF RECOVERING A LOST ANCHOR FALL ON?

A lost anchor could pierce into the hull of another ship. As such, the seabed should be kept clear of all obstructions, said Captain Tan.

“We do not want our seabed to be impacted by an anchor or anything on the seabed that can impede safe navigation of the ship,” he said.

Retrieving a lost anchor is the responsibility of a ship owner.

As such, while the MPA would embark on the operation of clearing the seabed, the shipowners would be held liable for the cost of all works involved, added Captain Tan.

ALTERNATIVES TO ANCHORING

Beyond the phenomenon of lost anchors, anchoring as a general practice has also received much negative attention for its effects on the marine environment.

“Anchors may damage habitats on the seabed such as coral reefs, and the materials of the anchor, anchor chain and anchor rope may be pollutive to the environment,” a spokesperson for Marine Stewards — a non-profit marine conservation organisation in Singapore — told TODAY.

Ms Sam Shu Qin, a co-founder of non-profit Our Singapore Reefs, which champions efforts to protect Singapore's coral reefs and marine biodiversity, added: “If it's the anchor itself, it's not so bad. If it comes with a chain, then it's more damaging.”

If anchors are lost near coral reefs, they could damage the reefs’ structural integrity and destroy homes of marine life.

Coral reefs would take very long to grow and recover from the damage, she said.

She has recovered two anchors – albeit smaller ones – during dive clean-ups between 2017 and 2023.

An alternative to anchoring would be mooring buoys — where boats are tied to a buoy — though this practice would work more for smaller boats, the spokesperson from Marine Stewards added.

Still, it would be “hard to not anchor” without proper infrastructure that allows for mooring among the boating community, said Ms Sam.

Authorities could consider designating no-anchor zones, especially in areas with rich marine life, or utilise markers to indicate shallow reefs or important reef areas, she added.

Captain Tan also highlighted that research and technologies could possibly aid port authorities in planning ships’ movement in and out of the berth, so that they would not need to anchor while waiting.

However, this is quite unlikely to be executed in Singapore as of now because of how busy its port is, which makes anchoring “inevitable”, he added.