CVA-01 - What was the RN carrier plan 1966-1976

[zen]

Not entirely clear as there was an effort to look at nuclear plant applicable for escorts as well as carriers and possible civil vessels.

Maybe crazy and financially prohibitive, but that was the times.

 

[Rule of cool]

The Royal Navy faced having a steam boilered carrier entering service in the 70s when her escorts were moving to gas turbines
However Fearless/Intrepid also used this system in the expected lifetime of CVA01
Without nuclear power the RN has had to abandon catapults and arguably build ships inferior to De Gaulle
.

The RN was a world leader in the adoption of gas turbines for ships, however in the decision window of the CVA01 it only had the COSAG County and Type 81 class with their 7,500shp GTs, and was planning the COSAG Type 82 with it's 20,000shp Olympus. IIUC the RN decided for all GT ships with the Type 42 and Type 21 in the late 60s.

I'd say that GT propulsion wasn't mature enough in the early 60s to put it into a carrier, but going steam wasn't a serious drawback as the RN was still building steam powered ships in good numbers until the late 60s and these ships will have long lives.

 

[Scott Kenny]

I don't think the British would scale up the PWR1, I think they'd buy or build the A3W.

Maybe. I mean, they don't need 200something thousand horsepower, they're building something between Midway and Forrestal (and are talking about only 135khp instead of 212khp of a Midway, or the 280khp of Forrestal!)

The challenge would be convincing Rickover to release one of his babies to the UK. As I understand it, there was a lot of arm twisting to get him to release the S5W, and that was a one time "here's the data package, that's all you get" with no continuing support.

You might be able to make an argument for 3 reactors, one per shaft. A C1W reactor (Long Beach powerplant) would be about right for that, 40-45kshp

Two reactors would be better in terms of packaging (two side by side instead of 2+1 or 3 in line), but that gets into weird steam-splitting options for the center shaft.

 

[BlackBat242]

Maybe. I mean, they don't need 200something thousand horsepower, they're building something between Midway and Forrestal (and are talking about only 135khp instead of 212khp of a Midway, or the 280khp of Forrestal!)

That would take 2 A3Ws - 70,000 shp each.

 

[Scott Kenny]

That would take 2 A3Ws - 70,000 shp each.

Which probably would be the simplest thing to do, if they could persuade Rickover to release the design.

Otherwise, gotta scale up what you have, but that'd be a big scale-up to 5x the output.

 

[zen]

There were studies. So it's not impossible. Just expensive.

 

[Scott Kenny]

There were studies. So it's not impossible. Just expensive.

Scale-up studies for PWR1?

 

[zen]

Scale-up studies for PWR1?

Honestly I don't know and those who have looked through the files at Kew find blank spaces.
Likely what exists is still secret.

 

[Scott Kenny]

Honestly I don't know and those who have looked through the files at Kew find blank spaces.
Likely what exists is still secret.

So you meant studies for an A3W-powered design?

 

[zen]

So you meant studies for an A3W-powered design?

I'd say beware of jumping to conclusions like that.

 

[GK Dundas]

I just stumbled upon the following whilst researching the CVA-01:

Life before Death: the 1963 decision to build the aircraft carrier CVA01​

Life before Death: the 1963 decision to build the aircraft carrier CVA01

Discussion of the planned British aircraft carrier CVA-01 tends to focus on its cancellation in 1966; surprisingly little attention is given to the initial decision to acquire it, taken only three years previously. This paper explores the arguments for and against the carrier, and the reasons...

www.kcl.ac.uk

Does anyone know if this seminar/presentation in 2018?


Regards
Pioneer

I would love to be able to read oa transcript of the event.

 

[Croatian Sailor]

A question: looking around drawings of CVA-01 project, I wonder why the landing deck isn't under larger angle? IIRC, it's 3 degrees, while say Audacious-class had more than 8 degrees or say Nimitz 9 degrees? Is there some technical reason for that?

 

[TinWing]

A question: looking around drawings of CVA-01 project, I wonder why the landing deck isn't under larger angle? IIRC, it's 3 degrees, while say Audacious-class had more than 8 degrees or say Nimitz 9 degrees? Is there some technical reason for that?

The limited angle was called the "Parallel Deck Lane Concept" of aircraft movement. Folded wing aircraft movements on the outside of the island along the "Alaskan Highway" was part of it. Earlier CVA-01 drawings showed a more conventional 7 degree angled deck.

 

[Croatian Sailor]

The limited angle was called the "Parallel Deck Lane Concept" of aircraft movement. Folded wing aircraft movements on the outside of the island along the "Alaskan Highway" was part of it. Earlier CVA-01 drawings showed a more conventional 7 degree angled deck.

But why? Did they think it will be more efficient for landing, launching, moving aircrafts on deck?

 

[EwenS]

But why? Did they think it will be more efficient for landing, launching, moving aircrafts on deck?

To quote Ian Sturton's article in Warship 2014

"A special working party investigated all aspects fo the ship. After careful consideration, a parallel deck arrangement with the landing runway at a small angle to the centre line was preferred to the usual angled deck. The advantages of the new arrangement were were real and substantial. During continuous flying operations, the extra width permitted aircraft on deck to circulate round the island; after landing, they would fold wings and taxi aft inboard of the island to an arming and refuelling point on the starboard side aft before going forward along the 'Alaskan Highway' outboard of the island to the catapult launch position. The total deck area increased by 2.8% while the useful parking area, clear of of landing and take-off operations, increased by 15%; two additional aircraft could be parked clear of the landing area and forward catapult. Night landings would be easier, as the ship's phosphorescent wake was more closely aligned with the axis of the landing area. These advantages more than offset the loss of one Sea Dart system.

A true parallel deck with separate landing and take off areas would have been preferred, but the ship was too small for this, and a small angle - 2.5° in the design study, 3.0° in the sketch design - had to be accepted."

The article has diagrams of both the final deck layout and a more usual 8.0° traditional angled deck from the Admiralty files that show the effects.

 

[Rule of cool]

IIUC the Arks Phantom refit included an 'Alaskan taxiway' for GSE like tow motors to transit outside the island. This worked well for the RN, decluttering the flight deck for aircraft movement. The 'Alaskan highway' was an expansion of this idea, to get aircraft administrative moves out of the way of operational moves.

 

[PMN1]

To quote Ian Sturton's article in Warship 2014

"A special working party investigated all aspects fo the ship. After careful consideration, a parallel deck arrangement with the landing runway at a small angle to the centre line was preferred to the usual angled deck. The advantages of the new arrangement were were real and substantial. During continuous flying operations, the extra width permitted aircraft on deck to circulate round the island; after landing, they would fold wings and taxi aft inboard of the island to an arming and refuelling point on the starboard side aft before going forward along the 'Alaskan Highway' outboard of the island to the catapult launch position. The total deck area increased by 2.8% while the useful parking area, clear of of landing and take-off operations, increased by 15%; two additional aircraft could be parked clear of the landing area and forward catapult. Night landings would be easier, as the ship's phosphorescent wake was more closely aligned with the axis of the landing area. These advantages more than offset the loss of one Sea Dart system.

A true parallel deck with separate landing and take off areas would have been preferred, but the ship was too small for this, and a small angle - 2.5° in the design study, 3.0° in the sketch design - had to be accepted."

The article has diagrams of both the final deck layout and a more usual 8.0° traditional angled deck from the Admiralty files that show the effects.

Did it say what size would be needed for a true parallel deck?

 

[EwenS]

Did it say what size would be needed for a true parallel deck?

No.

But looking at the deck plan, not having a true parallel deck may have been due more to the width required to accommodate the starboard wing tip line and / or the port wheel track line. At the very least more FD space was required aft on the port side. As it was the port wheel track line was very close to deck edge at forward end of catapult but further aft was much further inboard. Lose the small angle and it becomes much closer to the edge over a much longer distance.

So if the flight deck needed widened to get a fully parallel deck, what effect on waterline beam and ability to dock the ship, which was one limiting factor IIRC.

 

[Rule of cool]

No.

But looking at the deck plan, not having a true parallel deck may have been due more to the width required to accommodate the starboard wing tip line and / or the port wheel track line. At the very least more FD space was required aft on the port side. As it was the port wheel track line was very close to deck edge at forward end of catapult but further aft was much further inboard. Lose the small angle and it becomes much closer to the edge over a much longer distance.

So if the flight deck needed widened to get a fully parallel deck, what effect on waterline beam and ability to dock the ship, which was one limiting factor IIRC.

Yet another design parameter to take into account, ship designers must go berserk trying to design a ship to meet all sorts of requirements yet hemmed in by so many limitations. Frankly I'm amazed that ships get built at all.