Navy Lookout reports here that HMS Queen Elizabeth will stay in Scotland for longer than previously planned, reducing the time spent in refit during 2025.
HMS Queen Elizabeth will stay in dry dock in Rosyth longer than initially planned due to changes in the scope of work. The extension is necessary to address corrosion found on the starboard propeller shaft coupling, discovered during routine inspections, which led to the decision to replace both propeller shafts instead of just fixing the corroded one.
This mirrors the work done on the Prince of Wales last year following a similar mechanical issue.
Initially, it was intended to replace the shafts during the Queen Elizabeth’s planned refit in 2025, but this has been expedited, likely because the new components were available sooner than expected.
This approach aims to reduce the time spent in refit in 2025 and aligns with a new maintenance strategy focusing on more intensive upkeep while alongside to minimise dry dock periods.
You can read more from the excellent NavyLookout out here.
Seems reasonable, sort it out as needed. A stich in time and all that.
Better done while we’re at peace than closer to war.
Unbelievable, these new Carriers seem to spend more time having “maintenance” done than actually patrolling our seas. I wonder what the ships crew does during the extended down times ?
They work.
That’s the stupidest comment I have ever read on uk defence journal. All warships spend more time in maintenance than they do on patrol. A navy is doing incredibly well if 1/3rd of its ships are at sea at anytime.
Fair enough Jim, I come from a flying background where aircraft utilisation has to be in the air , not in the hanger……having said that , major checks do have to be done but a utilisation of 19% of the ships life at sea is unbelievable to a layman such as I am. I can see my knowledge is seriously lacking in the sphere of military operation.
Why? It’s not like an aircraft where you tell the pilot to take a nap and get a new pilot to fly it during the night, you need 1,600 people to operate a QE and it’s air wing. That means time in port for them to go on leave, see their families, do career and training courses and then work up to go to sea again (and remember unlike airline staff a ships crew doesn’t clock out at the end of the day, they stay on board for months). You also can’t just create a “ship simulator,” like you can for an aircraft, so if your crew is training they have to do it on board the actual ship.
But even then, when she’s “alongside” the crew won’t completely disperse, and there will be crew doing day to day mantenance. Only if the ship is in for a major dry dock (we are talking like a year) will the crew be reduced to a skeleton force and reassigned to other areas.
HANGAR.
flying background did you say?
Teehee 👌🙃🕳️
Yet you are happy to post I’ll informed comments!
Er go work on the other one, thats the benefit of having 2.
All warships spend a lot of time either in refit, mantiance or work up..the Elizabeth has been very hard worked over that 7 years it’s been in commission and has had a very high level of deployment or at readiness…
So if you look at the present plan for they US carriers you can see that the UK carriers are actually very busy:
US carrier deployment and maintaince plan
Deployed and at sea 19% of time
In harbour being maintained or worked up and ready to surge on 30 days notice 46% of time
In harbour deeper Maintance but able to surge within 90 days 11% of time
in refit and complete unavailable 24% of time
so as you can see a U.S. carrier will spend only 19% of its life actually at sea.
I would suggest reading the RAND paper “ aircraft carrier maintenance cycles and their effects” it would give you a good understanding of what should be expected of carriers being at sea vs having something fixed.
It’s amazing to think it’s been 7 years already.
It’s amazing that the UK was able to build two super carriers with little difficulty after not building carriers for 30 years and the program has experienced relatively few issues compared to CdG or Ford class, but the news never wants to publish stories like that.
QEC are based on a lot of the concept work for CVA01 which was updated.
Aircraft carriers were studied to death by generations of RN and RINA so there was a knowledge base.
Also derived from what compromises not to make from the Invincible programs – ie too small is a right problem that gets very hard to work around.
Appreciate the constructive and useful reply Jonathan. Thank you.
Are you a Bot Frank? Or Human?
Ancient Human 🙁
Just checking 😀
Beep boop beep. I’m a functional human. Beep beep not a robot.
It’s caused by the value for money syndrome in the ministry. I e the cheapest option.
Who can define value for money.
The most expensive option could be best value especially if it means top quality engineering.
But the ministry wants cheapest as value for money
New carriers!!! She’s ten years old. I’m sure your car would need some major maintenance in the time??
AND thats only two carriers. Imagine the logistics for 8+,in the70’s, and even more in ww2 .😁🕳️
This all seems like the kind of sensible pragmatic decision made between a competent defence contractor and an experienced navy. The kind of luxury a navy that operates two carriers can afford to do.
Seems sensible. I don’t know if there is a flaw in design or manufacture but good idea to get as.much done as you can.
That would be sensible, the RN is working these ships hard and making sure we have good availability mid 2020s is sensible considering the geopolitical situation and risks.
From what I’ve read the PoW also had a revised bearing lubrication system installed so I suspect they decided to just get that done as well to improve the life of the bearings and the shaft in the long run. Seems the original lubrication system wasn’t completely up to the job.
Before anyone moans however I would point out that this is what the car industry does with its prototypes. The difference is that our commissioned vessels are also the prototype. We can’t build a couple of hundred iterations to get it right the way they can.
I’m surprised by the corrosion. The Q.E. is after all a ship but I don’t pretend to be an engineer. The decision though seems to be very sensible.
The prototype had an issue.
The issue has been identified and fixed on #2.
Now #1 is in DD it is clear it needs the same fix.
So the same fix is applied.
That is how you make sure recurring problems are eliminated.
The alternative is to keep waiting till it breaks which reduces availability and you have unpredictable failures which look bad as well as being very bad for real life deployments.
👍
Corrosion is a common enough problem on propellor shafts even on quite small boats. There you have one end in the sea and another connected to the engine with an assembly of various metals. I’m not an engineer but that is my understanding.
BTW a friend of mine has a piece of HMS Hood. That part being a piece of one of her propellor shaft bearings which broke up under load. Its made of Lignum Vitae wood. So you see the carriers problems are nothing new to warships.
Thanks Jonno. Likewise I’m no engineer. I suppose I thought it was just something they would keep an eye on but as both ships have had problems…? Fascinating little bit of history on HMS Hood. Wood? Presumably very hard but even so. 🙂
In those days before roller bearings everything was greased up and had fixed metal or Lignum Vitae bearings. I have a 1921/22 motor launch with a metal bearings that need greasing up every day or so both on the propshaft and water pump.In fact the stern tube (bearing) is greased at the fore end and water lubricated at the very aft end. The finest Kelvin.
Hoods bearing is black Lignum Vitae wood and was probably greased up. I’m not sure about that not being a marine engineer.
LV is heavier than water so none would have floated up and survived her sinking.
Thanks again. 🙂
It’s about time they build a super dry dock in Portmouth.
Have you been to Portsmouth? There’s no room.
I think if you got rid of Gosport marina or the ferry terminal there might just be space but short of that, no chance. The Carriers take up a third of the channel width in their current position and most of the naval base is over a hundred years old.
I’d say start reclaiming land in Portland Harbour.
Sadly been there bought the T-shirt and ate the crayons
My case would be that we re-use the KGV dock in Southampton and have a Engineering barge to service it. Everyone goes on about security but that can be overcome surely. The other option is build one at Fawley or Portland the only suitable deep water sites on the South Coast.
Crazy to have no proper shipyard on the south coast; just retirement flats built on all the boatyards which is a disgrace too; we have our priorities all wrong.
There is suitable dry docks at locations in the U.K.
Having the trained staff and ability to fix the ships is a much more important issue.
The next issue would be what programs will need to be cut to pay for a super dry dock and the supporting infrastructure. Estimates I’ve seen go from £400m to a couple of billion.
The contract babcock rosyth have with the navy to have the dry dock available whenever it’s needed seems a good deal price wise.
Best choice change both, seems a bit of design issue but its being fixed. As long one carrier is always ready its fine.
It’s a shame they can’t just do the refit now, it would make more sense to get the major work done in one docking.
Problem is that a lot of the underwater work, hull inspections, sea valves, rudders, cathodic’s, shafts, props etc are driven by Mandated timelines. Usually, you do one each of an in-water hull survey and a dry dock survey in a 5-year period…if you’re lucky you can stretch it to 6 years.
Doing these surveys early resets the clock early and messes up future dry-docking surveys planned years in advance. With 2 carriers and in effect one dry dock that can take them, you cannot afford to do that. If you get the surveys out of sync, then it will knock on to the other vessel.
If it’s going to be a long dry dock 12 months+ perhaps some of the crew could go to getting an Albion ship sailing. I assume one is in a nearly ready to sail condition.
You don’t just swap ship to ship. Different courses for different systems. You have to be SQEP to operate them.
Took me over 3 months to do the courses to join Bulwark as the WE Warrant Officer. That was on top of the courses I already had under my belt from doing the WE WO job on T23s. Still took me 4 weeks onboard to qualify as OOD, OOQ and longer still to get an in depth handle on the WE and ME systems down to individual fuze panel and valve locations etc.
Or the view from a teenager I know (13) ‘if the UK is an Island that’s been making ships for thousands of years. Why can’t we make propeller couplings or align shafts?
It is a fair and reasonable question
Any large machinery that moves, rotates at varying speeds, followed by periods of not moving in a sea water environment is going to have issues at points.
Then take that the ships a basically prototypes and issues will happen. Being able to find and resolve the issues is really important.
Thank goodness the ships aren’t breaking down on the other side of the world a long way from a friendly port.
They have a huge drydock in Sydney.
From a teenager who’s me:
Perfectly understandable
We can align shafts.
To be fair any decent engineering company can align shafts.
I have helped to do optical alignment on a shaft line many times. From the prop hub, through the A frame, intermediate support, stern seal to the gear box.
Its not quick but once you know what you are doing its relatively straight forward.
The corrosion that was developing in the couplings was the issue. It’s not like the red rust you see on an old car. This is small areas, hard to see, under the coupling protective cover and acting on a molecular level. You don’t need large corrosion pits for it to begin but once it does all sorts of chemical reactions and cathodic and anodic reactions start to contribute. This can result in hydrogen embrittlement and stress fractures in the steel crystalline matrix and that’s not something you want on a coupling designed to take 10s of thousands of shaft horsepower through it.
Armed with that info Gunbuster,I’d be interested to see what probs the likes of the wartime HMS Manxman, fast ship, had with shafts and associated fittings.😗🕳️