These heavy-duty concrete structures are known as 'mattresses' – and, appropriately enough, they are destined for the sea bed.

Eastern Daily Press: Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines. Picture: Nick Butcher.Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines. Picture: Nick Butcher. (Image: Archant © 2018)

The 2,000-tonne shipment is headed for Malta, from where the 360 pads will be shipped on to protect an underwater pipeline from a platform 100km north of the Libyan capital Tripoli.

But yesterday they were being loaded in Great Yarmouth by SPS, the company which has spent the last six months manufacturing a total of 1,033 mattresses. Two further shipments will depart from Dundee.

SPS, of Southtown Road, has also invested more than £200,000 in 70 additional 'speed-loaders' for the project.

Managing director Mark Buckle said the deal was a substantial one for the company.

Eastern Daily Press: Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines.Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines. (Image: Archant © 2018)

'To secure a contract of this size at this time was a major win for us, and took a lot of hard work over a couple of years,' he said.

Eastern Daily Press: Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines.Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines. (Image: Archant © 2018)

Eastern Daily Press: Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines.Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines. (Image: Archant © 2018)

Eastern Daily Press: Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines.Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines. (Image: Archant © 2018)

Eastern Daily Press: Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines.Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines. (Image: Archant © 2018)

Eastern Daily Press: Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines.Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines. (Image: Archant © 2018)

Eastern Daily Press: Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines.Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines. (Image: Archant © 2018)

Eastern Daily Press: Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines.Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines. (Image: Archant © 2018)

Eastern Daily Press: Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines.Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines. (Image: Archant © 2018)

Eastern Daily Press: Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines.Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines. (Image: Archant © 2018)

Eastern Daily Press: Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines.Concrete 'mattresses' being loaded on to a ship in Yarmouth Harbour. Concrete specialists SPS in Yarmouth have won a contract to supply concrete 'mattresses' to Malta to protect pipelines. (Image: Archant © 2018)