At the end of World War One steel, the preferred ship-building material, was scarce, as was skilled labour. On both sides of the Atlantic shipbuilders fell back on reinforced concrete as a temporary solution to the problem.
The use of concrete as a building material is no new phenomenon; the Roman Empire pioneered its use in construction and one of the ancient aqueducts still supplying modern Rome was made of the material. If ships suffered light damage, in theory they could be repaired with an application of fresh cement. In practice, costs of construction were much higher than estimated.
Cretehawser, built at Southwick by the Wear Concrete Building Company (a subsidiary of Swan Hunter), was launched on March 15th, 1919. She was a sea-going tug of 262 tons, 162 feet long with a beam of 28 feet and draft of 13 feet and was followed by sister ships Creterope, Cretecable, Creteboom and Cretestem. In service, Cretehawser towed several loaded barges often of coal but the imposition of dock fees on all three craft rather than just the tug made the practice totally uneconomic.
The abandoned vessel has lain beside the Wear since 1942 after her withdrawal from service during the Depression. Initially she and other vessels were gutted, being intended as makeshift breakwaters. The first German air raid on Sunderland changed matters for the Creteships. Creteboom suffered a direct hit and was sent to the bottom of Hendon Dock creating a huge navigation obstacle of shattered concrete. A major salvage operation was mounted to raise the debris from the dock. Sister vessel Cretehawser, now engineless, and a sitting duck for enemy bombers, was towed out of dock up-river and grounded, opposite the old Hylton Colliery, to prevent her suffering the same fate as Creteboom.
In 1962, 20 years after her grounding, a spokesman for the River Wear Commissioners said “Cretehawser is a dead duck as far as we are concerned. She was put there and forgotten and I suppose she will stay there forever”. Despite the steering limitations, sailors who served in the concrete vessels spoke of them with some affection. Mr Ramsden of Grangetown said “Cretestem was a good a ship as I sailed in”. In the Great Gale of 1920 she did salvage work on the Tyne (during a local tug operators strike) when many ships broke loose (including a captured German liner).
The concrete tugs’ added weight was a definite advantage when towing, and in docking, to reduce heeling. They had a crew of 12. The foc’sle had a turtle back making it seaworthy in bad weather and shielding the windlass and anchor gear. The galley and entry to officers’ quarters were between funnel and foc’sle. Concrete barges were usually around 1,000 tons and built, like other ships, on keelblocks. Some yards used precast sections, others used steel sheets as lining instead of wooden shuttering so the finish was smoother. Waterproofing compound was added to the concrete but construction work was weather-dependant as frost prevented work and intense heat dried the hull too quickly.
In Gloucester, Ferro Concrete’s yard employed 380 workers who turned out both barges and massive 800 ton Creterock – commissioned by the Shipping Ministry. The latter, with a length of 180 feet and beam of 31 feet was launched into the Gloucester Ship Canal broadside on, drenching unprepared spectators on the far bank. She was followed by five further Gloucester vessels with the suffix Crete-- Road, River, Ridge, Ravine and Rampart. Designed initially to carry ammunition and other military supplies, they were launched too late to be used in the Great War.
Of the barges made in Gloucester, around 20 were dumped in the mud to strengthen the bank between the Severn and the Sharpness Canal. The Purton barge graveyard, as it is known locally, gave up one of its craft to serve as an exhibit at the National Waterways Museum Gloucester Docks (see photo). At the time of writing, the barge is not on view at the Docks but there is a concrete narrowboat on site.
After World War One, 21 firms were building concrete boats at the behest of the Ministry of Munitions but the economies of using unskilled labour were sadly offset by the higher cost of materials. A steel barge could be made for £17,000 but a concrete one cost a whopping £27,500. Out of 154 vessels ordered only 54 barges and 12 tugs were completed, as their original use for ammunition carrying was of less importance.