Robot 'sentries' to protect rusting Titanic wreck

The ocean explorer who led the team that discovered the remains of the Titanic has drawn up plans to dispatch deep-water robots to the floor of the North Atlantic to conserve the wreck.

It was 100 years ago this week that the liner set sail from Southampton for New York on her doomed maiden voyage. Maritime officials and experts have warned that the wreck is rusting away.

The US Coast Guard recently wrote to the International Maritime Organisation asking for a ban on ships dropping rubbish or releasing sewage within 10 nautical miles of the site. Robert Ballard, a professor of oceanography at the University of Rhode Island, said last week that he will apply for a permit from US authorities to conduct an ambitious operation nearly 212 miles beneath the surface.

He has seen significant decay in the wreck since he found it in 1985 as bacteria colonies, possibly fed by human waste and rubbish, have eaten away at the steel hull.

Small submarines carrying high-paying tourists are also accused of accelerating the damage by landing on the wreck - a claim strongly denied by expedition operators.

The wreck will also come under the protection of Unesco, the United Nations cultural agency, after the 100th anniversary of its sinking on Saturday.

Underwater robots that would clean the ship's hull and coat it with protective anti-fouling paint have been used to treat the hulls of oil tankers.

"When I first came to the ship in 1985, I saw original anti-fouling paint on the bottom and no corrosion there," Ballard told National Geographic.

"It works, but obviously they didn't think they'd need to paint the whole ship with anti-fouling paint."

He said the technique was needed "so the hull doesn't splay open and expose the highly preserved interior with its precious contents". Ballard also proposes robots be used as "sentries" to monitor the visits by tourist submarines that he is convinced have damaged the wreck.

The Titanic is "being killed by love", he said last week.

Describing the wreck as "under siege" by natural forces, careless visitors and rogue salvage operators, he outlines his fears that it will not survive another 100 years in Save the Titanic, a documentary to be broadcast on the National Geographic cable channel this week.

But Rob McCallum, the general manager of Deep Ocean Expeditions which will this summer run a $60,000-a-head cruise and submarine trip to the site, said it was "nonsense" to suggest that the $50 million submersibles were knocking into the wreck.

He said the vessels effectively "hovered" weightlessly while the tourists looked at the remains.

"They are delicate, so a pilot who 'drove around bashing into things' would probably come to grief pretty quickly," McCallum added.

"The biggest fear any sub pilot has is entanglement, so they keep away from the wreck and usually face towards it so that they can keep an eye on it so as to gauge relative position and the current."

He said the Titanic was deteriorating because it is a metal ship that has been lying in the ocean for 100 years, rather than because of the occasional visit by a small tourist submarine.

In what are effectively unpoliced waters, there are also fears that unscrupulous salvage teams with small remotely operated underwater vehicles are plundering the site.

Senator John Kerry recently introduced a bill into the US Congress designed to toughen up protection of the site.

James Delgado, chief of the maritime heritage office at the National Oceanic and Atmospheric Administration, said: "The Titanic can be a model for how humanity treats the world's underwater cultural heritage. But we cannot do nothing."