Maritime accident investigators are wrestling with the puzzle of how a bulker inexplicably sailed off course to ground on a Mauritius reef — with catastrophic consequences for the island's marine environment.

The ship's master, voyage recorder and AIS data will provide critical evidence of the bridge officers' decisions that led up to the grounding of the 203,000-dwt Wakashio (built 2007) on 25 July.

The vessel's owner, Nagashiki Shipping, said there were no reported mechanical faults.

But the ship’s voyage plan from Singapore to Brazil — taking it 20 miles (32 km) south-east of the island — was first plotted thousands of miles away by the ship’s charterer Mitsui OSK Lines.

The Japanese shipping company uses a sophisticated centralised fleet operation centre in Tokyo to navigate its vessels, using the safest and most energy-efficient routes.

MOL's Safety Operation Supporting Center provides precise meteorological and routing data on its fleet of 800 owned and operated ships.

Legal responsibility

But, ultimately, it is the legal responsibility of the master to carry out the sailing plan, who, in this case, is directly employed by the vessel’s owner, Nagashiki Shipping.

MOL confirmed it was involved in the route planning of the Wakashio but is already distancing itself from the navigational decisions that were taken prior to the grounding.

In a statement to TradeWinds, MOL said: “The master was given a recommended routing, but the route is not compulsory and it is the captain’s sole decision to divert based on the conditions at sea.”

MOL said it had no idea why the ship drifted off course. “We do not have information on when or why the vessel diverted as it is under investigation by the local authorities.”

But MOL said its information “indicates that there was a diversion”.

MOL said in a press conference this week that its ship operation centre is not sophisticated enough to provide minute-by-minute sailing data on its fleet. It was difficult to pick up that the vessel was sailing too close to the island, the company said.

The full financial liability is likely to fall on owner Nagashiki Shipping, which is covered by the same third-party liability insurer as MOL, the Japan P&I Club.

Through the International Group of P&I Clubs' claims pooling arrangement there is potentially up to $3bn of primary and reinsurance cover available.

The owner, by accepting the liability as the employer of the master, can limit financial liability under the International Convention on Civil Liability for Bunker Oil Pollution Damage.

Environmental costs

The Bow Jubail spilled 270 tonnes of oil in the port of Rotterdam in 2018 and ran up claims of $50m. Photo: The Netherlands Coastguard

The convention, to which Mauritius is a signatory, is likely to limit oil pollution liability to the tens of millions of dollars rather than the hundreds of millions it could potentially run into.

More than 1,000 tonnes of fuel oil spilled from the Wakashio, destroying livelihoods and wildlife, as well as beaches and reefs on the eastern side of the island.

As an indication of the potential claims values involved in pollution incidents, a small spill of 270 tonnes from the 37,499-dwt Bow Jubail (built 1996) that was contained in the port of Rotterdam two years ago ran up claims of $50m.

But problems could arise if Mauritius is unable to meet the outstanding clean-up and compensation costs after the owner has limited liability.

This would leave Mauritius the option of challenging the shipowner's right to limit liability or to pursue action against the charterer to recover funds.

Tempting target

Tokyo stock-listed MOL, one of the world’s top five largest shipowning groups, could present a tempting target for Mauritius to pursue recovery.

Even though colliding with an island in the vast Indian Ocean with modern navigation technology should be unthinkable, similar incidents have happened.

In March 2011, the 75,000-dwt bulker Oliva (built 2009) hit the island of Tristan da Cunha in the middle of the Atlantic Ocean, spilling 1,700 tonnes of fuel oil and ruining the local fishing industry.

In 2010, the 24,400-dwt product tanker Sichem Osprey (built 2009) sailed into Clipperton Island in the middle of the Pacific. In both instances, the accidents involved crew mistaking the islands for rain clouds on a radar.