Island that’s been in the wrong place for 85 years
THE Royal Navy has discovered a remote Pacific island declared the “most polluted in the world” has been marked in the ‘wrong place’ – for 85 years.
British sailors now say Henderson Island is one mile south of the position used on charts used by mariners all over the world since 1937.
The Royal Navy has been using navigational charts supplied by the Taunton-based UK Hydrographic Office (UKHO) for more than 225 years while, over the past 15 years, the majority of the Fleet has been navigating with digital charts.
The UKHO employs some 900 staff in the Somerset town and is an executive agency, sponsored by the Ministry of Defence.
It moved to Taunton from London in 1941.
According to the Navy, key areas and seas regularly used are well covered by the electronic system – which not only ensures navigational accuracy, but allows sailors to “interrogate” key features such as landmarks, buoys and depths.
Henderson Island in one of four islands in the remote Pitcairn chain.
The island is uninhabited and about the size of Oxford. Chile lies 3,600 miles to its east and New Zealand 3,200 miles to its south-west.
Of the Pitcairn chain, only Pitcairn itself is populated – with a population of about 50, who are descended from the mutineers of HMS Bounty and their Tahitian companions.
The remote chain has only had some satellite-based data collection, which had already highlighted the inaccurate positioning on historical charts, so HMS Spey offered to assist with data gathering.
She is not a dedicated survey vessel, but navigator Lieutenant Michael Royle used radar imagery gathered by Spey’s sensors and GPS positioning, overlaying the details on the existing charts of the Pitcairn chain.
“In theory, the image returned by the radar should sit exactly over the charted feature – in this case, Henderson Island,” Lieutenant Royle explained.
“I found that wasn’t the case – the radar overlay was a mile away from the island, which means that the island was plotted in the incorrect position when the chart was first produced.
“The notes on the chart say that it was produced in 1937 from aerial photography, which implies that the aircraft which took the photos was slightly off in its navigational calculations.”
Despite its isolation, Henderson has earnt the unfortunate title “most polluted island in the world”, due to Pacific currents that have dumped masses of debris on its shoreline.
It has been estimated that 270 objects every day wash up on its beaches – with as many as 40 million items of plastic and rubbish scarring Henderson’s landscape.
HMS Spey confirmed the error as part of efforts to check and update charts of waters around British Overseas Territories across the globe.
The work by Spey is part of much wider Government programme to update maritime charts of waters around the UK’s Overseas Territories and improve navigation using sonar, airborne laser techniques and satellites to better understand, manage and protect the marine estates of these territories.
Henderson Island was last visited by the Royal Navy in late 2018, when HMS Montrose conducted an environmental survey to study the impact of plastics in the oceans.
“Scientists in the UK have really scant data about the ocean in this region – its salinity, temperature, water pressure and the like,” Lt Royle added.
“They are keen to understand climate change in the area.”
The ship also conducted patrols in the waters around the islands to deter and defend against illegal fishing, in partnership with the UK’s satellite monitoring programme run by the Marine Management Organisation.
Portsmouth-based Spey is on a five-year mission to the Indo-Pacific region with her sister HMS Tamar, a mission which has already seen her help the people of Tonga in the wake of the recent tsunami which affected the Pacific nation.