When Douglas Mapp and Julie Smith launched their artistic messages in bottles into the sea off Yarmouth as part of a pioneering project, they expected nothing else to be seen or heard of them.

When Douglas Mapp and Julie Smith launched their artistic messages in bottles into the sea off Yarmouth as part of a pioneering project, they expected nothing else to be seen or heard of them.

But out of 60 bamboo containers containing sketches of the Norfolk coast to be tossed into the waves, the two belonging to the boyfriend and girlfriend are the only ones to have so far shown up - on Terschelling island off the Dutch coast.

In a further remarkable coincidence, the containers were found by the owner of the island's Shipwreck Museum, whose most prominent display is devoted to the story of HMS Lutine, a frigate that sank on a sandbank off the island with its cargo of gold as it was sailing from Yarmouth to Hamburg in 1799.

Art students from Great Yarmouth College and local schools had been invited to do sketches of the coast to be put inside the eco-friendly bottles in a project inspired by the marine charity CoastNet's Holding Back the Tide initiative, which aims to increase understanding of coastal issues.

The bottles each contained an invitation to anyone finding them to do a sketch of their own coastline and return them to project co-ordinator Mark Wood, a lecturer at the college.

Julie, 38, who lives with her partner in Northgate Street, Yarmouth, said: “We launched the containers into the sea at different times and they were all mixed up so it is an incredible coincidence - and quite a romantic one - that it was our two that were washed up together on the same beach.”

Douglas, 34, who is on the same Great Yarmouth College Btec art and design course as Julie, said: “We are all wondering now whether other ones will be discovered, perhaps further along the coast towards Denmark.”

His sketch of the town's Haven Bridge and Julie's view down the river towards Breydon Bridge were discovered on Christmas Day and December 27 - four weeks after they entered the sea - by museum owner and wreck diver Hille Van Dieren, 62, and his son Guus.

He said: “We have a special section for messages in bottles and regularly search up and down the beach in our four-wheel-drive vehicle. We have put the containers on display with other items washed up on the beach, including a message in a bottle from the Isle of Wight.”