Piloting The Aircraft Carrier: Queen Elizabeth: Jerry Purvis

October 13th, 2018 by JCB
Posted in Technical and Training | No Comments »

 

On 3 rd July 2008 the contract to build two new aircraft carriers for the Royal Navy was signed. The vessels are sometimes described as supercarriers by the media. They displace approximately 65000t, over three times the displacement of their predecessors, the Invincible class carriers, and are 285m LOA. They are the largest warships ever built in the United Kingdom and will be the largest warships ever in the Royal Navy, and are named HMS Queen Elizabeth and HMS Prince of Wales.

The vessels were built by Aircraft Carrier Alliance (ACA), a joint venture with the Ministry of Defence, Babcocks, BAE and Thales. The vessels were built in modular form at six shipyards throughout the UK, with final assembly at Rosyth on the River Forth in Scotland.

The Association of Forth Pilots first became involved in the project in 2008. With delivery of the first carrier expected to be 2017 and the second in 2019 this was clearly going to be a long-term project and continuity of who would be involved with it was essential. Three First Class Pilots were appointed to the project – one consideration being that they had to be young enough to see the project through to completion. The three ‘lucky’ pilots are Paul Wibberley, Jerry Purvis and Willie Terry, who were very quickly nicknamed The Carrier Queens by their colleagues.

L-R: Capt Jerry Purvis (Forth Pilots) / Commander Jerry Kyd (CO of QNLZ) / Capt Paul Wibberley (Forth Pilots) / Capt Willie Terry (Forth Pilots)

Each vessel consists of three main hull sections, each delivered on submersible barges from around the UK and then floated off for entry into the building dock at Rosyth. The completed hull with superstructures was then floated out of the building dock for outfitting alongside in the main basin before finally exiting through the main basin direct entrance into the River Forth on final departure for sea trials.

Simulation of all aspects of the carrier project was essential and proved to be invaluable. All stakeholders (pilots, tug masters, Royal Navy, MOD and ACA) attended simulations at South Tyneside College. These simulations were the focal point for marine operations for the carrier project. Many techniques were considered, simulated and discounted until imaginative and innovative solutions to the ship handling challenges of the modular blocks and completed carrier were found. For example, the building docks at Rosyth date from the early 20 th century – they were built for the original Dreadnought battleships – and do not have shore powered winches fitted to assist vessels. So, to control the exit of the newly built carrier from the building dock, a 32t bollard pull tug was lifted by shore crane and placed in the dock ahead of the ship.

 

There were also many similarities of the departure sailing of the carrier with that of large cruise vessels from the building yard in Papenburg, Germany. However, their technique of strapping a tug across the bow on a temporary cradle structure had to be discounted. With a six metre tidal range on the River Forth, removing such a structure was too time consuming once the carrier had cleared the main basin direct entrance. She had to get down the Rosyth approach channel and into the river during the High Water slack water period. Also, cruise ships leaving Papenburg had their engines available – the carriers were effectively being moved dead ship.

 

Over 100 simulations were carried out covering all parts of the project, including contingency plans such as the departure having to be aborted and the carrier being returned to the main basin. With it being such a complex operation, the use of storyboards proved essential, giving everyone involved a clear timeline, schematic of the plan and their part in it, and shared mental model of how the operation was to proceed.

Eleven tugs were utilised for the departure operation, with up to eight fast at any one time. With uncertainty over the first carrier’s departure date, right up until the last minute, the booking of towage became problematic, and two weeks before departure it became apparent that five of the tugs in the plan would not be available. Portable Pilot Units (PPUs) were utilised to best effect, for the exit from the building dock and for the departure from the main basin into the River Forth. The equipment used was an RTK unit supplied by Trelleborg. ‘Tram Lines’ superimposed on the PPU display gave a highly accurate parallel indexing effect for the departure through the main basin direct entrance.

As all pilots who have handled aircraft carriers will be aware, one of the biggest challenges is the lack of good conning positions either on the vessel’s centre line or with a good view down the ship’s hull. With such small clearances on departure when passing through the main basin direct entrance, it was essential that the conning pilots had a clear view. The solution arrived and was to have two of the pilots on a cherry picker platform hanging down the ship’s hull from underneath the aft aircraft lift. The third pilot on the navigating bridge is ready to take over control of the vessel after she clears the confines of the main basin’s direct entrance.

Piloting from a cherry picker!  

 

L-R : Lt. Cdr. Jez Brettel  / Pilot ; Jerry Purvis  / Pilot: Paul Wibberley 

Departure of the first carrier HMS Queen Elizabeth – was finally confirmed as 26 th June 2017. Tug bookings were finalised. Operations commenced at 0900 with toolbox talks, and letting go of last lines at 1400. Everything proceeded to plan – almost. Not everything can be simulated or predicted, and the carrier set further to the north in the main basin than anticipated– much to the consternation of the ship’s staff. Not unusual for pilotage operations, though, and the carrier was lined up for the direct entrance and departure without drama. She cleared the main basin at 1600 and was anchored in the river by 1730.

Queen Elizabeth had to depart Rosyth at High Water but had to wait until Low Water to have sufficient clearance for her air draft to get under the three Forth Bridges and proceed to sea. Half an hour before Low Water she picked up anchor and transited the bridges and the River Forth under her own power.

It was a long day for all involved, but the operation went very much to plan, and resulted in one very happy Commanding Officer and three relieved ‘Carrier Queens’.

The second vessel – HMS Prince of Wales – is expected to proceed on sea trials in 2019.

Apart from the ITN news screen grab, all photos reproduced by kind permission of the Forth Pilots.