Royal Navy Aircraft carrier breaks down again.

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Re: Royal Navy Aircraft carrier breaks down again.

#81 Post by TheGreenAnger » Wed Sep 07, 2022 6:14 pm

G-CPTN wrote:
Wed Sep 07, 2022 6:06 pm
TheGreenAnger wrote:
Wed Sep 07, 2022 12:13 pm
It is said that the US Nimitz class carriers can make better than 35 knots.
Does it plane?
Not as much in the way that the Zumwalt class of destroyers get up on the plane...


http://www.military-today.com/navy/zumwalt_class.htm




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Further delays to repair of carrier

#82 Post by TheGreenAnger » Mon Oct 03, 2022 7:19 pm

The departure of Royal Navy aircraft carrier HMS Prince of Wales to head for repairs in Scotland is understood to have been delayed because engineers were unable to remove the damaged propeller in time.

The aircraft carrier has been due to sail to Rosyth where it will enter dry dock to fix damage that stopped her from deploying on US-based exercises.

The mechanical fault was discovered just 48 hours after she left Portsmouth for America.

The £3bn warship broke down off the Isle of Wight in August after sailing from Portsmouth Naval Base to take part in flight trials and diplomatic visits in the US.

Inspections by divers and engineers found that the 33-ton starboard propeller – the same weight as 30 Ford Fiesta cars – had malfunctioned, with a coupling holding it in place breaking.

The 65,000-tonne ship was brought back to Portsmouth for further examination by engineers from Babcock before the decision was taken for it to travel to Rosyth, where it was built, to undergo the repairs in dry dock.

Divers surveyed the damage to the aircraft carrier's starboard propellor and shaft, following her breakdown.

A Royal Navy spokesperson said: "The full extent of the repairs will be known once the ship has entered dry dock. We are committed to getting HMS Prince of Wales back on operations, protecting the nation and our allies, as soon as possible.”

The propeller shaft is made up of a number of 'steel poles' joined together, with the engine on one end and the propeller on the other.

Each of the poles is joined together with a 'shaft coupling' which is where the fault has been identified on the Prince of Wales.

Work was continuing during the weekend to remove the giant propeller but it is understood that this was not completed in time for the planned sailing on Monday afternoon, according to the Press Association.

Divers are continuing to work on the ship but it is not expected to sail, assisted by a tug, until at least later this week because of a storm with heavy winds forecast on Wednesday. The Navy has not commented on how long the repairs are expected to take and how long HMS Prince of Wales will be absent from its role as NATO flagship, but it is understood to be months rather than weeks.

Its sister ship HMS Queen Elizabeth changed its autumn plans to travel to the US to take over some of the planned engagements, including hosting the Atlantic Future Forum in New York – a defence conference aimed at strengthening UK and US bonds.

Rear Admiral Steve Moorhouse, director of Force Generation, who is responsible for making sure Royal Navy ships are ready to deploy, previously explained the fault suffered by HMS Prince of Wales.

He said: "Royal Navy divers have inspected the starboard shaft of the ship and the adjacent areas and they have confirmed there is significant damage to the shaft on the propeller and some superficial damage to the rudder but no damage to the rest of the ship.

"Our initial assessment has shown that coupling that joins the final two sections of the shaft has failed.

"Now, this is an extremely unusual fault and we continue to pursue all repair options," he added.
From Forces.Net


https://www.forces.net/qe-class-aircraf ... ay-repairs
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Re: Royal Navy Aircraft carrier breaks down again.

#83 Post by FD2 » Mon Oct 03, 2022 8:54 pm

I'm not sure why they have to remove the propeller before the tow unless there is no way of locking the shaft to prevent further damage, as the prop tries to turn under tow. It seems logical to have the propeller with the ship for the people at Rosyth to complete the job.

They've had plenty of time to de-store and de-ammunition the ship since it was towed alongside.

Maybe time to expand a suitable dry dock in Portsmouth or Devonport that can take these ships.

I'm glad I now know what 30 Ford Fiestas weigh. :))

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Re: Royal Navy Aircraft carrier breaks down again.

#84 Post by TheGreenAnger » Mon Oct 03, 2022 9:05 pm

FD2 wrote:
Mon Oct 03, 2022 8:54 pm
I'm not sure why they have to remove the propeller before the tow unless there is no way of locking the ***** to prevent further damage, as the prop tries to turn under tow. It seems logical to have the propeller with the ship for the people at Rosyth to complete the job.

They've had plenty of time to de-store and de-ammunition the ship since it was towed alongside.

Maybe time to expand a suitable dry dock in Portsmouth or Devonport that can take these ships.

I'm glad I now know what 30 Ford Fiestas weigh. :))
I saw her tied up in the dock from the air when I flew up the coast a fortnight ago. She was definitely riding very high in the water and the unloading had definitely taken place. An impressive looking ship, sadly stranded.

This article implies the prop had been removed!

https://www.naval-technology.com/news/m ... 20Scotland.
HMS Prince of Wales has spent weeks alongside the Princess Royal Jetty, as engineers work with divers and naval architects from Babcock and the UK Ministry of Defence’s (MoD) Defence Equipment and Support organisation to determine how to bring the vessel back to operational capability.

The Prince of Wales’s 33-tonne starboard propellor has also been removed while alongside in Portsmouth ahead of its journey to the Babcock’s Rosyth dockyard in the Firth of Forth, meaning the vessel will transit under reduced movement on its port propellor alone, likely with assistance from sea-going tugs.

At this stage, it is unlikely a timescale for repairs has been fully mapped out, with greater inspections required when HMS Prince of Wales enters drydock.

However, should the worst fears be realised and the starboard propellor shaft be badly damaged or bent, repair work could take a considerable amount of time and effectively see the carrier unable to undertake operations for several months, potentially into the back end of 2023 or even 2024.
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Re: Royal Navy Aircraft carrier breaks down again.

#85 Post by TheGreenAnger » Mon Oct 03, 2022 10:40 pm

I wonder how the lightly loaded ship, without the weight of the propeller, will fare with the tidal reach on the Firth of Forth insofar as that might result in a smaller time window to pass under the bridges that span the water?



https://www.dailymail.co.uk/news/articl ... h-Sea.html
Measuring 920 feet in length, the vessel squeezed out of Rosyth dockyard, leaving the Scottish basin where she was assembled this Thursday.

The process of getting the four-acre military operating base on to the Firth of Forth represented one of the most delicate manoeuvres the warship would have to undertake.

Navigators, pilots and tug boats had the slimmest of margins to deal with as they guided the 65,000-tonne carrier out of the basin through a narrow opening during high tide.

The gap the aircraft carrier had to pass through is little more than 130 feet wide - allowing around three feet of clearance either side and one-and-a-half feet between the bottom of the ship and the sea bed.
Even trickier when running one engine and riding even higher than before!
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Re: Royal Navy Aircraft carrier breaks down again.

#86 Post by Undried Plum » Tue Oct 04, 2022 1:47 am

The poxy thing needs ballast.

It's good for nothing else to carry.

Then, chop it up for nails.

Both of the Blaircraftcarriers were a stoopid idea.

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Re: Royal Navy Aircraft carrier breaks down again.

#87 Post by FD2 » Tue Oct 04, 2022 2:34 am

I wonder how the lightly loaded ship, without the weight of the propeller, will fare with the tidal reach on the Firth of Forth insofar as that might result in a smaller time window to pass under the bridges that span the water?

That won't present a problem - the Forth Bridge centre span is high enough, likewise the Forth Road Bridge and Queensferry Crossing.

The difficult part at Rosyth is getting in and out of the enclosed basin. The span of the caisson is only just a few feet wider than the width of these carrier's hulls, so it's a delicate operation. The basin is sealed off and only open at high tide so that ships inside are always at the same height relative to the jetty. When I was serving in a frigate at Rosyth I remember seeing our first Polaris boat Resolution gliding through into the basin for her first dry docking.

I can't see POW's serviceable port shaft being used to get into the basin, it will be warped and manoeuvred in with tugs. I think the dry dock orientation means she will be turned to starboard and pushed straight in, there to be lost to service for a long time. The port shaft will certainly be used on the way north of course and they will wait for a very calm moment to get her in the basin.

Both of the Blaircraftcarriers were a stoopid idea.

Agreed - a bribe to Broon's voters in his Kirkcaldy constituency. Unfortunately the country is stuck with the damned things and I can't ever see the money being released to convert them to 'proper' carriers.

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Re: Royal Navy Aircraft carrier breaks down again.

#88 Post by llondel » Tue Oct 04, 2022 3:09 am

FD2 wrote:
Mon Oct 03, 2022 8:54 pm
I'm glad I now know what 30 Ford Fiestas weigh. :))
They've put on a bit of bloat. I had a 1999 model and that was only just over a ton. Newer ones are a Leonberger heavier.

Perhaps they could use a few of them as ballast?

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Re: Royal Navy Aircraft carrier breaks down again.

#89 Post by TheGreenAnger » Tue Oct 04, 2022 3:58 am

FD2 wrote:
Tue Oct 04, 2022 2:34 am
The difficult part at Rosyth is getting in and out of the enclosed basin. The span of the caisson is only just a few feet wider than the width of these carrier's hulls, so it's a delicate operation. The basin is sealed off and only open at high tide so that ships inside are always at the same height relative to the jetty. When I was serving in a frigate at Rosyth I remember seeing our first Polaris boat Resolution gliding through into the basin for her first dry docking.

I can't see POW's serviceable port ***** being used to get into the basin, it will be warped and manoeuvred in with tugs. I think the dry dock orientation means she will be turned to starboard and pushed straight in, there to be lost to service for a long time. The port ***** will certainly be used on the way north of course and they will wait for a very calm moment to get her in the basin.

Both of the Blaircraftcarriers were a stoopid idea.

Agreed - a bribe to Broon's voters in his Kirkcaldy constituency. Unfortunately the country is stuck with the damned things and I can't ever see the money being released to convert them to 'proper' carriers.
Thank you for that insight FD2.

As for the rest, now HMS Prince of Wales is as much good to the defence of the realm as an empty cake tin is to a tea party, and is likely to be so for many more months.

I assume that the conversion, that will never come, would involve the fitting of steam catapults?

PS - I see we have a misfiring auto censor at work here in the quote algorithm. I fear that the word shaft is now deemed to be offensive, like shut or maybe even shift! =))
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Re: Royal Navy Aircraft carrier breaks down again.

#90 Post by FD2 » Tue Oct 04, 2022 4:23 am

Steam cats were always a problem with conventionally powered carriers - it took a load of steam to launch a Phantom or a Buccaneer. That's not such a problem with the nuclear powered carriers as long as the condensers are working properly to produce fresh water. Ships with 'condenseritis', like one I was in during a Beira Patrol, meant we had to go to a dockyard to sort the problem out and in our case we were extremely unpopular with the ship we had just relieved, which was on its way to the Seychelles after a lengthy patrol. X(

The Americans seem to be having some success with their magnetic jobbies (EMALS) https://en.wikipedia.org/wiki/Electroma ... nch_System so that would be a sensible option when the Americans have ironed out all the snags. ;)))

Some hope. [-X

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Re: Royal Navy Aircraft carrier breaks down again.

#91 Post by TheGreenAnger » Tue Oct 04, 2022 4:50 am

Reading that interesting link reference electrically powered catapults kindly posted by FD2, it seems that for a while the UK toyed with the idea of using the same on the Queen Elizabeth-class carriers.
United Kingdom
Converteam UK were working on an electromagnetic catapult (EMCAT) system for the Queen Elizabeth-class aircraft carrier. In August 2009, speculation mounted that the UK may drop the STOVL F-35B for the CTOL F-35C model, which would have meant the carriers being built to operate conventional takeoff and landing aircraft using the UK-designed non-steam EMCAT catapults.

In October 2010, the UK Government announced it would buy the F-35C, using a then-undecided CATOBAR system. A contract was signed in December 2011 with General Atomics of San Diego to develop EMALS for the Queen Elizabeth-class carriers. However, in May 2012, the UK Government reversed its decision after the projected costs rose to double the original estimate and delivery moved back to 2023, cancelling the F-35C option and reverting to its original decision to buy the STOVL F-35B.
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Re: Royal Navy Aircraft carrier breaks down again.

#92 Post by Boac » Thu Oct 06, 2022 3:44 pm

Whilst talking carriers, the nuclear-powered USS Gerald R Ford (14ft longer than the Nimitz-class carriers!!), has set sail on its fist deployment. It is the largest warship in the world and has been designed with more than 20 new technologies, including an electromagnetic rather than steam-generated catapult system.

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Re: Royal Navy Aircraft carrier breaks down again.

#93 Post by G-CPTN » Fri Oct 07, 2022 1:05 pm

The departure of HMS Prince of Wales for repairs in Rosyth is on hold again, despite the warship having been listed to sail today.
The ship had been due to sail at 10:50 but divers are understood to be carrying out more inspections this morning.
HMS Prince of Wales is now listed to sail again at 22:55 today but it is not clear at this stage if there will be further delays.

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Re: Royal Navy Aircraft carrier breaks down again.

#94 Post by TheGreenAnger » Tue Oct 11, 2022 9:08 pm

En route to the drydock.

0_imageedit_71_9417900543.png
0_imageedit_71_9417900543.png (267.57 KiB) Viewed 957 times

The photo, shows HMS Prince of Wales being tugged along the Firth of Forth. The highest element of The Prince of Wales looks to have been lowered so that it could pass underneath the Bridge at South Queensferry.

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Re: Royal Navy Aircraft carrier breaks down again.

#95 Post by FD2 » Tue Oct 11, 2022 9:24 pm

Thanks TGA. I think the lowerable mainmast was always a feature as they were built in Rosyth and would always have to pass under the bridges to get to sea.

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Re: Royal Navy Aircraft carrier breaks down again.

#96 Post by Undried Plum » Wed Oct 12, 2022 3:17 am

FD2 wrote:
Tue Oct 11, 2022 9:24 pm
would always have to pass under the bridges to get to sea.
And back again, as was always expected that the poxy things would have to do.

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Re: Royal Navy Aircraft carrier breaks down again.

#97 Post by FD2 » Wed Oct 12, 2022 3:33 am

And back again, as was always expected that the poxy things would have to do.

Why was that 'always expected', U.P?

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Re: Royal Navy Aircraft carrier breaks down again.

#98 Post by TheGreenAnger » Wed Oct 12, 2022 3:48 am

FD2 wrote:
Tue Oct 11, 2022 9:24 pm
Thanks TGA. I think the lowerable mainmast was always a feature as they were built in Rosyth and would always have to pass under the bridges to get to sea.
The radio mast was designed from the outset with a hinge to allow transit under those bridges, as you say FD2. Apparently, with the mast folded, the clearance under one of the bridges can be a little as 6 feet.
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Re: Royal Navy Aircraft carrier breaks down again.

#99 Post by G-CPTN » Wed Oct 12, 2022 5:16 am

How much does the draught vary according to load? Plimsol etc?

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Re: Royal Navy Aircraft carrier breaks down again.

#100 Post by FD2 » Wed Oct 12, 2022 6:24 am

Sorry G-CPTN, I haven’t a clue, that’s a hard one!

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