Aircraft carrier ballast

HMS Queen Elizabeth & HMS Prince of Wales



Royal Navy


BAE Systems – Surface Fleet

Location type


The challenge

Produce and install 800 tonnes Ultiballast for the Royal Navy Flag Ship – the aircraft carrier - HMS Queen Elizabeth, and HMS Prince of Wales. It was critical that the ballasting program for the vessels was met but also be flexible to accommodate and not delay or compromise other operations and the testing and commissioning critical paths. A program risk identified was that significant long duration road works with significant diversions had commenced on the delivery route to the shipyard, which would disrupt or delay the delivery schedule of Ultiballast affecting the material quality and specification and installation program.

The project program required the installation of ballast should be undertaken over two mobilisation visits for each ship. First, visit placing Three hundred and seventy-five tonnes and a second visit some months later to complete the final one hundred and twenty-five tonnes. Due to program slippage on the overall build of the ships caused by adverse weather conditions, it became necessary to review the methodology and accelerate the installation program to meet the clients critical path commissioning period.

Our solution

To remove the risk of delays with deliveries a mobile production plant was transported to Scotland and assembled close to Rosyth Naval Dockyard. The mobile production plant was erected, tested, and commissioned in one week, with tests and trials on machinery and electrical systems completed, quality assurance trials were undertaken to ensure the design specification was met.

Three hundred and seventy-five tonnes of ballast was produced, delivered and pumped through an array of pipework set up by our installation team onboard HMS Queen Elizabeth with the vessel dry in dry dock.

Working closely with BAE ship build teams it was identified that the second installation could be completed after HMS Queen Elizabeth had launched out and was floating alongside for fit-out completion. We also identified from the learnings from the Queen Elizabeth installation that the full quantity of 400 tonnes could be installed in the carrier HMS Prince of Wales in one visit as opposed to two visits, this collaborative approach provided our client with the opportunity to fully complete the installation of four hundred tonnes of ballast into HMS Prince of Wales at the same time as the remaining one hundred and twenty-five tonnes of concrete ballast was installed in HMS Queen Elizabeth.

Results and benefits

Having a flexible can-do attitude and detailed understanding and knowledge of our product, processes, and procedures we successfully produced, delivered, and installed eight hundred tonnes of Ultiballast safely, early on the program, to specification and within the agreed outturn cost for the aircraft carriers HMS Queen Elizabeth and HMS Prince of Wales. Our collaborative approach provided the client with significant cost and program savings for the project.

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