There are over 30 documented shipwrecks on Rhossili Beach

Two steel posts are sticking up at Llangennith on Gower, and although visible at low tide they are hidden under water as the sea comes in.

There are warnings of a serious injury if someone were to hit one of them.

More than 30 wrecks have been recorded along the beach and researchers are due to visit on Wednesday to investigate.

Richard Dallimore of Llangennith Surf said the posts were about 18 - 24in (45 - 61cm), and about 150m (490ft) down the beach, more or less opposite the main footpath from the car park.

There are over 30 documented wrecks on the beach Jim Phillips

"The sand has been shifted quite a lot by the winter swell we've had this year," he said.

"The posts are in the busiest area where everyone ends up.

"The beach is known as a sandy beach and there will be a lot of people unaware that they are there."

He said they could cause someone a serious injury if they were to collide with one of them on what is Gower's most popular beach for surfing.

Jim Phillips, who has researched many shipwrecks around the Swansea and Gower coast, said he planned to visit on Wednesday.

The wreck of the Helvetia can be found further along the beach

"My best guess at the moment from what I've heard is that it is a shipwreck or at least part of one," he said.

"There are over 30 documented wrecks on the beach from paddle steamers to a destroyer which broke its line near there."

Along the beach towards Worms Head the oak carcass of the Helvetia, which was shipwrecked in 1887, is still visible and is one of the most photographed sights on Gower.