Aircraft Carriers

[wuzak]

• Non-Nuclear and Gas Turbine powered: They can be started rapidly, probably more efficient than boilers and overhauls don't require one to gut the whole ship as on a nuclear carrier
  
• Something between the size of the Essex & Midway or the Midway: Big, but not too big
  
• Angled-deck length, arrester hooks, deck elevators, and catapults able to operate planes in the Enterprise or Nimitz range
  

Steam power from boilers has some advantages for a big carrier:
- supplies steam to the catapults.
- good, flexible, power control for the multiple power cycles a carrier goes through.  A carrier spends a surprising amount of time throttling up and down for flight operations.  Gas turbines are most efficient at higher rpm's.
- efficient.

dis-advantges:
- space and weight requirements for the plant and trunking.
- would need to re-constitute the expertise to run and overhaul steam plants.
- separate fuel for the boilers and the air-wing. 

A steam boiler could absolutely use the same fuel as the air wing, but your probably would not want to.

There is also the option of a combined cycle plant - a gas turbine and steam turbine combined. Usually used in power generation, often with natural gas fuel, which can give very high efficiencies and still provide process steam.

Since a high proportion of power generation is still provided by fossil fuelled steam plants I'm sure that getting that expertise wouldn't be too difficult.

[sandiego89]

• Non-Nuclear and Gas Turbine powered: They can be started rapidly, probably more efficient than boilers and overhauls don't require one to gut the whole ship as on a nuclear carrier
  
• Something between the size of the Essex & Midway or the Midway: Big, but not too big
  
• Angled-deck length, arrester hooks, deck elevators, and catapults able to operate planes in the Enterprise or Nimitz range
  

Steam power from boilers has some advantages for a big carrier:
- supplies steam to the catapults.
- good, flexible, power control for the multiple power cycles a carrier goes through.  A carrier spends a surprising amount of time throttling up and down for flight operations.  Gas turbines are most efficient at higher rpm's.
- efficient.

dis-advantges:
- space and weight requirements for the plant and trunking.
- would need to re-constitute the expertise to run and overhaul steam plants.
- separate fuel for the boilers and the air-wing. 

A steam boiler could absolutely use the same fuel as the air wing, but your probably would not want to.

There is also the option of a combined cycle plant - a gas turbine and steam turbine combined. Usually used in power generation, often with natural gas fuel, which can give very high efficiencies and still provide process steam.

Since a high proportion of power generation is still provided by fossil fuelled steam plants I'm sure that getting that expertise wouldn't be too difficult.

Agree that ship steam plants can burn different fuel, but as you point out "you don't want to"- there are big differences in aviation fuel and what is normally used in ship boilers, and havy bunker fuels are cheaper.  The inverse is not true- you would not want to put a heavy fuel oil into your shiny new F-35 

Yes a combined cycle plant might be interesting, but I would think using conventional fuels, and perhaps diesel/electric for nomal cruising and gas turbines for higher speeds like the newer America/Makin Island LHD's.  I would have doubts about a navy wanting natural gas on board a warship.

The expertise I was referring too was in Navy circles- there are fewer crews and yards that have the expertise to man and overhaul steam plants.  Tons of gas turbine techs in the enlisted ratings and engineering officers- fewer with steam experince. Agree it would be manageable.       

[KJ_Lesnick]

wuzak

A steam boiler could absolutely use the same fuel as the air wing, but your probably would not want to.

Tell me about it

There is also the option of a combined cycle plant - a gas turbine and steam turbine combined. Usually used in power generation, often with natural gas fuel, which can give very high efficiencies and still provide process steam.

When were they first used?

[wuzak]

There is also the option of a combined cycle plant - a gas turbine and steam turbine combined. Usually used in power generation, often with natural gas fuel, which can give very high efficiencies and still provide process steam.

When were they first used?

Some time ago.

I think the Germans were even experimenting with it for power production in WW2.

[wuzak]

Yes a combined cycle plant might be interesting, but I would think using conventional fuels, and perhaps diesel/electric for nomal cruising and gas turbines for higher speeds like the newer America/Makin Island LHD's.  I would have doubts about a navy wanting natural gas on board a warship.

I would think that the combined cycle plant would probably use heavy fuel, as per normal on ships, and operate as generators for power production.

Certainly the Navy would want to limt the number and size of pressure vessels containing combustible fuels.

[MikeD]

How well were the Malta class designed as carriers? Were they an efficient design (ie able to launch/recover a decent portion of the very large planned air group in a single strike) that benefited from the experiences of WW2 or would the RN have been stuck with large carriers that were badly thought out if they'd have been built?

How long, realistically, could they have remained viable as front line carriers (with upgrades to electronics and cats as required, the addition of angled decks as they come into use etc) with the Royal Navy? Could they have operated a decent (maybe an air group of 36 or 48 (ie 3 or 4 squadrons worth) fast jets plus a few AEW/ASW types?) number of Phantom and Buccaneer for instance?

[sandiego89]

I think they could have been similar to the Midway class in the US Navy, which proved capable, adaptable and quite long lived.  Not as efficient as the true post war US super carriers, but still quite useful.  With a 1950's refit with angled deck, stronger (and a third) catapults, lifts and arresting gear, I think they would have made a perfectly good transition to the jet age.  The Midways never deployed with Phantoms, but the Royal Navy showed a willingness to operate Phantoms and Buccaneers from carriers smaller that the Midways. Reasonable to see 3 squadrons of fast jets aboard, plus Gannets and helos. 48 Phantoms and Buccs (plus others) would likely be pushing it. They are large aircraft.   

Seeing the Ark Royal made it to 1978, I would say late 1980's would be reasonable. Midway made it to the early 1990's.  Midway really pushed the limits of modernization, amazing to see the size of the overhang and deck size compared to her original fit and her sisters.  She rode poorly. 

There are some good drawings of "what if" Malta's if you do a google image search.

I would see the elevator arrangement as the major drawback, especially with a post war-angled deck.  In her original straight deck configuration, the two port side elevators would have been fine, but would have been sub-optimal with an angled deck. Both would likely be in the "foul area" making them essentially useless during landing operations.  The other 2 elevators are centerline, both complicating flight operations.  The US recognized this with the first super carriers and even with the Midways, and moved to deck edge elevators/lifts where possible.  Without a elevator re-arrangement the Malta would have been sub-optimal in terms of launch and recovery and re-spotting. 

I believe they only had two forward catapults, undoubtedly these would have been improved with greater capacity and stroke length, but only 2 catapults is limiting.  A additional angled deck catapult would have been useful. Quite a few US and UK WWII era carriers added these when the angled decks were added.   

So I would recommend an angled deck, a third catapult and some elevator re-arrangement.  A great WHIF subject. Perfect for a Falklands fit 

-Dave       

[DarrenP2]

my what if Falklands is 2 malta class, and 3 LPH based on the Albion, Bulwark and Centaur. 3 Light Carriers based on Hermes batch of the Albion carrriers.
Air wins on the big carriers
F4K
Buccaneer
Seaking
Wessex
Gannet AEW4

Airwings on the LPH

wessex HU5
Sea King HC4
Scout AH1
Gazelle AH1

Airwings on Light Carrier

Buccaneer
Sea Harrier FRS1
Harrier GR3
Sea King
Wessex

[PR19_Kit]

One would almost suggest that if such a magnificent fleet and air groups had existed there never would have been a need for them down in South Atlantic anyway. 

Would have been pretty awesome seeing that lot sail off down Spithead nonetheless.

[DarrenP2]

yes it would have been an impressive sight

[DarrenP2]

 More impressive 1977 Queens Silver Jubilee Review at Spithead

British and British Built Aircraft and Commando Carriers

HMS Malta
HMS Gibraltar
HMS Ark Royal
HMS Hermes
HMS Polyphemus
HMS Monmoth
HMS Albion (LPH)
HMS Bulwark (LPH)
HMS Centaur (LPH)
HMAS Melbourne* (Ex HMS Eagle)
HMAS Sydney (Ex HMS Majestic)
HMAS Brisbane (LPH) (Ex HMS Terrible)
HMCS Bonnaventure (Ex HMS Audacious)
HMCS Ontario (LPH)(Ex HMS Powerful)
INS    Vikrant (Ex HMS Hercules)
INS    Virat    (Ex HMS Leviathan)
PNS   Babur    (Ex HMS Magnificent)
ARA   Independencia (Ex HMS Warrior)
ARA  Veinticinco De Mayo (Ex HMS Venerable)
BNS  Minas Gerais  (ex HMS Vengence)
BNS  Sao Paulo (Ex HMS Ocean)
CNS  Almarante Latorre (Ex HMS Glory)
CNS Huascar (ex HMS Colossus)
HMNlS Karel Doorman (LPH)(Ex HMS Arrogant)
FNS Arromanches (LPH)(Ex HMS Elephant)

*Jointly manned by RAN & RNZN

[MikeD]

Some interesting thoughts, thanks.

I'm going to have to see if I can dig out some accurate measurements for the Malta's hangar and see what it could actually hold.

[dy031101]

I am posting this picture here only because I don't think that the Republic of China (a.k.a. Taiwan) Navy would embarrass themselves by posting in an official naval museum an artist impression, however crude it might be, of a future ROCN fleet that they aren't serious about trying to build.  I think it is likely to be depicting a LHA rather than a CVL though.



And the bitter lesson of their 1950s and early-1960s naval clash with the PLAN hasn't been entirely forgotten- for ships that aren't meant to do shore bombardment missions, having punchy, rapid-reacting, rapid-firing guns is more important than having big guns.

The original picture HERE!

[ysi_maniac]

Studying config of carriers during WWII I noticed that only japanese  tried funnel out of island. in my opinion funnel in the opposite side to island looks sensible for the sake of balance. In the same way, exhausting sideways or downwards sounds sensible too.

Why these  aiternative dispositions were not continued?

[sandiego89]

Studying config of carriers during WWII I noticed that only japanese  tried funnel out of island. in my opinion funnel in the opposite side to island looks sensible for the sake of balance. In the same way, exhausting sideways or downwards sounds sensible too.

Why these  aiternative dispositions were not continued?

A funnel opposite the island would interfere with wave offs, especially last second ones. Wave offs are done when the approach is not stabilized for a good, safe, landing, or the deck is not clear.  It would also put exhaust gasses right into the flight path of aircraft turning downwind, creating a "burble" of hot air, upsetting the turn to approach.   It would have also greatly complicated the move to the angled deck which was just around the corner.  A stack to port would be right where you would want to put the angled deck.

As for sideways and downward funnels, perhaps they would not take the exhaust far enough away from the ship, her aircraft and crew.  I recall several pictures of the Kaga showing tons of exhaust emissions running down the side of the ship.  Even with water spray to knock the smoke down, some would likely get into the hanger bay, or be deposited on aircraft and crews on the aft deck.  Not good.  It is best to have funnels as high a possible, or at the extreme aft end. The amount of trunking to get the stack to the aft end of a carrier would take away from flight decks or hanger parking.  Also up to WWII carriers, most were designed to operate aircraft when the ship was going astern (backwards). These carriers could make impressive speeds astern.   A side or rear stack would likely put excessive exhaust on the forward part of the ship, including the navigation bridge.  Again up high is best.     

The Kaga:
  https://upload.wikimedia.org/wikipedia/commons/thumb/0/0e/Japanese_Navy_Aircraft_Carrier_Kaga.jpg/300px-Japanese_Navy_Aircraft_Carrier_Kaga.jpg