A widespread sea rescue search using a helicopter and a lifeboat and costing nearly £12,000 to mount, was sparked off by the drunken activities of two Falmouth Marine College students, Truro magistrates court heard this week.

They got away unchallenged after stealing a dinghy and a 28-foot yacht, but when they saw themselves on television caught by CCTV cameras taking the dinghy, they gave themselves up.

Before the court on Monday was one of the pair, Joel Bagley, aged 20, now living in Hereford, who was before the court for sentence for taking a dinghy and a yacht without consent.

Sarah Topham, prosecuting, said Bagley and a colleague by the name of Quinn had become extremely drunk and took a dinghy from a pontoon near Falmouth Docks intending to row it round the harbour.

While doing so they came across the 28-foot yacht and boarded it, soon to find themselves drifting towards Pendennis headland. Panicking, they started looking round inside the boat for flares or some means of signalling.

They then tried to put up the sails, but there was no wind. They decided to abandon the yacht and rowed the dinghy back to the shore, leaving the larger boat adrift.

When daylight broke the yacht was seen drifting and a search and rescue operation set up when it was feared that the owner had fallen overboard. A rescue helicopter was airborne for one and a half hours, costing £10,393 and the life boat service activated costing a further £1,129. When it was ascertained that the owner was well and at home the lifeboat towed the yacht back to its mooring.

When a CCTV camera was checked it showed Bagley and Quinn taking the dinghy. Their pictures were shown on television and having seen them, the two gave themselves up.

Ms Topham said in their search of the yacht and trying to put up the sails, the two men had done damage amounting to £500. The dinghy was recovered undamaged.

Robin Smith, defending, said this had been a prank in drink that went horribly and expensively wrong.

Bagley was remorseful about his part in it, which was completely out of character.

Quinn had already been dealt with by another court and was given 150 hours of unpaid work to do and told to pay £500 compensation to the yacht owner.

Bagley was given similar hours of work to complete and ordered to pay £500 compensation, half to go to the dinghy owner to compensate him for the cost of recovery of his boat, and half to the RNLI.

Chairman David Lugg told Bagley that as he had had an expensive education, society had a right to expect better behaviour from him. "You risked your own lives and the rescue service personnel and through what was a false alarm they were unavailable for a genuine rescue."