An engineering challenge involving massive sections of submarines at BAE Systems’ Barrow shipyard which once took several days to complete can now be finished in just a matter of hours.
Manoeuvring two pressure hull units – the ‘slices’ of submarines that are eventually joined together to create the completed craft – is a delicate operation.
When both weigh several hundred tonnes yet need to be lined up with pinpoint accuracy, getting it right takes experience and precision.
The new Central Yard Facility, opened in May 2018, is where these giant sections of the Royal Navy’s next generation of nuclear submarines are aligned and welded.
A new design of transportation beam means that they not only support the sections of submarines during construction but also allow the integration of new jacking and alignment features which enable the hull sections to be set with unheard-of precision.
Combined with a new unit alignment system the team managed to connect two units with an impressive 1mm level of accuracy in just a few hours.
“We’ve never been able to do this before,” Alan Phizacklea, production engineering department consultant, BAE Systems said. “This system uses electronic trace wires to allow the team to monitor exactly how close the units are and make delicate adjustments to get them as perfectly aligned together as possible. It’s also made the working practices much safer.”
The ability to guide hydraulic jacks with such precision means units can not only be lined up towards each other horizontally and vertically but also side on too, offering engineers a 3D perspective.
“By making use of the adjustable beams we’ve been able to line up the first unit with a second unit with far greater accuracy, first time,” Will Spain, senior engineering manager, BAE Systems said.
“Hydraulics, connected to the beams, together with precision crane work means we can align the units far more easily.
“Whereas in the past it could take days to get it exactly right, we’ve managed to carry out the same manoeuvre in less than a shift allowing welding to take place more quickly and with even greater confidence. This has also improved the quality of the finished pressure hull structure.”