appears to have begun with a loose wire in the vessel's GPS antenna.

Washington Lloyd's List correspondent Mr. Joel Glass took a closer look at the accident -- which occurred off Nantucket Island, Massachusetts. The article said the examination came after a decision by the US National Transportation Safety Board to issue an urgent advisory for ship operators to review the design of their integrated bridge systems.

The Nacos 25 bridge system is used on the Royal Majesty and at least 200 other vessels, said its manufacturer STN Atlas Elektronik of Hamburg.

Mr. Glass said the Nacos 25 can use its autopilot to automatically steer a vessel on a predetermined route using a variety of data including longitude, latitude and the ship's speed and manoeuvring characteristics.

This data is taken from the vessel's GPS and Loran systems and is accompanied by the autopilot's "dead reckoning system''.

He said the Nacos 25 had alarms for when there was a discrepancy between the ship's two sources of positional data.

However the bridge officers would never know one system had defaulted because the alarms were in an area of the bridge where the officers were unlikely to see or hear them.

After the grounding the ship's officers said they found the shield wire disconnected from the GPS antenna which meant the autopilot was only receiving one source of positional data from the Loran system.

Mr. Glass said the alarms would not have been set off because there would not have been two sets of positional data to have a discrepancy between.

The ship would have been relying solely on its "dead reckoning''' system -- which does not take into account the effects of wind, current or sea conditions on a ship's position -- when it ran aground.

After the grounding the ship's officers checked the other positional data from the Loran system which showed the ship was on top of the shoal.