The production of ultra-large naval cylinders as far ahead as 2020, is currently being planned as a result of a major new export order won by the UK’s Chesterfield Special Cylinders Ltd.

The company, based in Sheffield, is set to supply sets of high-pressure air cylinders to be built into the next generation of nuclear-powered submarines (SSNs) for the French navy – nicknamed the ‘Barracudas’.

The contract, estimated to be worth around £3m over a seven year period, was signed with DCNS after the French naval constructor was awarded the first phase of the programme by the French procurement agency (DGA).

The cylinders will operate in the Barracudas at 275 bar (275 times atmospheric pressure) and will provide back-up breathing and operational systems power.

Optional additions
The initial contract with DCNS covers the first four boats, scheduled to be built over the period 2013 to 2022. DCNS has an option to purchase further sets of the large diameter cylinders for the remaining two - if and when the DGA confirms the second tranche.

Discussions are also thought to be continuing with DCNS, ascertaining whether Chesterfield will supply ancillary fittings for the cylinders.

Metallurgists from both companies worked together to develop the actual design of the cylinders, to meet the demanding technical specification that would satisfy all the Barracuda’s operational requirements.

Lengthy negotiations with DCNS dealt with technical and commercial factors, including the control of the relatively unusual steel procurement route by which the steel tubes will be made ready for processing into cylinders in Sheffield, as well as validation of the special steel processing requirements of the tubes prior to, and following, the critical neck forging process.

Confidence in experience
The through-life performance of all on-board systems of the six Barracudas has received special focus by DCNS from the outset of the tendering process.

Chesterfield provided performance data - derived from a comparison study of materials in service for similar submarine applications - to show that the cylinder design will comfortably outlast the planned service life of the Barracudas.

Stephen Butler, Chesterfield’s International Sales Development Manager, explained, “Ultimately DCNS has bought into the fund of experience which Chesterfield possesses in making high-pressure naval cylinders. This confidence embraces our technical abilities in design, manufacturing and testing.”

“More than a century of supplying the Royal Navy,” he continued, “including the ‘Trident’ and current ‘Astute’ submarine fleets, plus our supply to the French ‘Scorpene’ programme, has served us well in the winning of the contract.”

The first cylinders will be despatched from Sheffield to the DCNS shipyard in December 2009. It is expected that the first boat will be delivered to the French Navy in 2016.