WesWorld

Gentlemen,

start your engines, keep your calculators busy and lend me your ears. I would like to get your input on a problem I have. I´ve discussed it with some of you already but maybe there are still some things you like to comment.

Technical situation in the early 1920s:

The men responsible for the building programs of the RSAN are watching the experiments of that Mitchell-guy in the USA closely. They find it very interesting that land-based bombers can cause lethal damage to heavily armoured warships - at least unless those targets are moving and fighting back. The technical development of aircraft has led to a point where one cannot ignore them anymore when cruising close to a coast. The chance to get hit and maybe badly damaged might be marginal at best with current planes but it can be expected that soon planes will be available that are no longer flimsy, get extended range and can carry higher loads of bombs. Thus fleetoperations close to bases of land-based aircraft will need aircover within the next years.

The same men have also noticed that floatplanes can act as scouts for the fleet but that they will lack the climbing rate, speed and power to protect a fleet from land-based bombers once those start to grow larger and less flimsy. The solution to this problem are ship-borne fighter planes. And if one is able to handle these kind of planes one surely can handle scouts as well. Thus ships with landing decks are needed to provide the aircover necessary and to scout for the fleet.


Technical development of aircraft carriers early in the 20s:

The men responsible for the building programs of the RSAN do not only watch those Mitchell-guy-experiments closely - they also follow the development of aircraft carriers among foreign navies. To keep pace with those developments the RSAN has converted a liner too in 1917 for experimental use (CVX Wim Kraash, assigned to the Navy R & D Institute Durban). Further more there are experiments with a cruiser that gets temporarly platforms attached for and aft from time to time at the Navy Academy in Durban. Finally, there are people at the Durban Institute of Science and Technology (DISAT) – which is part of the Durban University – who work on material, procedures and technologies to make the sea-borne use of airplanes possible in large scale. The results of all these new developments and tests are gathered and analysed. Many questions are still not answered but it is expected that – from a technical point of view - it will be possible to launch a building program for purpose build carriers in the middle of the current decade.


The geographical and military situation early in the 20s:

The SAE currently consists of three large territories between which contact can only be held via shipping. The seaways used form a large triangle across the southern Atlantic Ocean with Cape Town, Montevideo and Douala forming the edges. Other important seaways lead to the Netherlands East India and India via the Indian Ocean and across the Middle and North Atlantic towards the USA and Europe. If a war cannot be avoided it is lethal for the SAE to protect these sea routes and thus fleet operations of the RSAN will be focused on these seaways. Planes based on foreign possessions along those routes have to be rates as possible threads.

Those planes can be based

- on British Tristan da Cunha threatening the route Cape Town – Montevideo
- on British Ascension threatening the route Montevideo – Douala
- in French Ghana causing a thread to the route Montevideo – Douala
- in Iberian Angola threatening the route Cape Town – Douala
- in Italian Somalia threatening the route SAE - India
- on British Tschagos Islands (also known as British Indian Ocean Territory) threatening the routes SAE – NEI and SAE – India.

The range and bomb load of those planes, which will undoubtedly increase over the years, dictate where they can reach important seaways between the SAE and its possessions and allies. It is therefore necessary to protect the RSAN warships operating on those areas against enemy airplanes in the future. To do so the carriers have to be able to keep up with the latest and future designs of the battle fleet which means a minimum speed of approx. 29kn and a range of no less than 5000nm at an average speed of 15kn. For the case that weather does not allow flight operations the carriers themselves have to be protected against bombs from land-based planes as good as possible. On the other hand there is no need to arm them with guns larger than 15cm. Large enemy ships will be driven off by the battle fleet but the carrier should be able to defend itself against attacking torpedo boats.

Currently the RSAN consists of three large parts: The First Fleet base in South Africa, the Second fleet based in South America and the Northern Fleet based in Cameroon, each of which contains at least one Battle Squadron and attached cruisers and light crafts. All these fleets will need airborne elements in the next 5 to 10 years. In addition there should be at least one carrier that can act as compensation if one of the carriers detached to one of the three fleets needs repairs and maintenance.

The Cleito Treaty allows an allotment of 110,000ts dedicated for aircraft carriers to the RSAN with no limit in number of hulls. There are no capital units that will be re-designed as carriers so that the maximum tonnage per single ship is 22,000ts. Further more CVX Wim Kraash is to be rated as experimental and will be taken out of commission within the rules of the CT.

Financial and material constrains, limited manpower and slips as well as the impossibility to provide enough trained crews at once make it necessary to stretch the building program for carriers over several years. It will not be possible to lay down 110,000ts of carrier tonnage within two or three years. This is not seen as a disadvantage because it offers a chance to learn from early designs and avoid failures that will undoubtedly happen in the beginning.


With this background information at hand, what kind of carrier building program would you start? How many hulls of what size at which date and why? Please note: I´m not asking for a specific design here. The questions are meant more generally.

Thank you for your input,

HoOmAn

Just thought I should point out that the Chagos Islands, historically known as the British Indian Ocean Territory, have been claimed as a part of India since the sim began.

But that's a minor point. To answer your question...

South Africa appears to view carriers as defensive tools, at least during the early '20s. If so, embarked aircraft will consist of fighters and scouts/light bombers. Larger bombers and torpedo bombers may not come around for a little while.

To me, there are two considerations with carriers that need to be kept in mind:

1) As the size of the airgroup is the square root of the ship's miscellaneous weight, larger carriers are not necessarily the most efficient way to maximize your fleet air arm.

2) Carriers are vulnerable to catastrophes. A single torpedo set off an avgas explosion that destroyed Taiho; Lexington had a not dis-similar fate. And the Japanese carriers at Midway suffered as badly as they did because they happened to have fueled and loaded strike forces on deck. Heck, even one good hole in the deck results in a mission-kill. But the cost of a catastrophe is less if the carrier is smaller.

I'd suggest South Africa begin its building program with a pair of small carriers - 10,000 tons. You can put 30 kts, 30-40 planes, and a couple inches of deck armor on that size of hull. If the airgroup is mostly fighters, that's enough to fend off a strike force from a 22,000 ship.

These "jeep carriers" won't be first-rate combat units, but later in life, they'll still make effective escort carriers for convoys, training, ASW work, and so forth. Early on, they can also exercise against each other to develop your anti-carrier doctrine.

After that, step up to an evolving series of medium carriers. I'd be thinking six 15,000 ships, built in pairs a few years apart. A ship of this size can do 31+ knots, carry 50 - 60 aircraft, and mount 2 to 3 inches of deck armor. These would be large enough to carry mixed strike forces and have an offensive role.

So:

1924: lay down 2 CVE of 10,000 t - in service by 1926.

1928: lay down 2 CV of 15,000 t - in service 1930. Incorporate operational experience of CVEs, which will be in service for two years by the time these are laid down.

1931: lay down 2 CV of 15,000 t - incremental improvements of the previous pair.

1934: lay down 2 CV of 15,000 t - incremental improvements of the previous pair.

Deployment: early on, keep the two CVE in a central location where they can deploy to hot spots quickly and also work against each other in exercises. Once there are four carriers, you can assign one to each fleet and have a fourth free for repairs, training, or other deployment. With 6+ carriers, you can decide whether to spread them around or concentrate some in dedicated striking forces.

Quoted

Originally posted by The Rock Doctor
South Africa appears to view carriers as defensive tools, at least during the early '20s. If so, embarked aircraft will consist of fighters and scouts/light bombers. Larger bombers and torpedo bombers may not come around for a little while.

That´s correct. The battleship will remain the main weapon of my fleet - the shield and sword to defend my Empire.

Quoted

Originally posted by The Rock Doctor
1) As the size of the airgroup is the square root of the ship's miscellaneous weight, larger carriers are not necessarily the most efficient way to maximize your fleet air arm.

2) Carriers are vulnerable to catastrophes. A single torpedo set off an avgas explosion that destroyed Taiho; Lexington had a not dis-similar fate. And the Japanese carriers at Midway suffered as badly as they did because they happened to have fueled and loaded strike forces on deck. Heck, even one good hole in the deck results in a mission-kill. But the cost of a catastrophe is less if the carrier is smaller.

I also thought about having several small CVs to maximise my air arm but on the other hand every torpedo hit and serious bomb hit will most likely result in me loosing one of those carriers because they will be relatively fragile.

I may have more hulls with more hull but I will also loose them much faster than I would loose bigger units. One simply can´t put a 70mm armoured deck on a 10kts carrier if that carrier should also have decent speed, range and - that´s why I build it - a large air group.

Quoted

Originally posted by The Rock Doctor
I'd suggest South Africa begin its building program with a pair of small carriers - 10,000 tons. You can put 30 kts, 30-40 planes, and a couple inches of deck armor on that size of hull. If the airgroup is mostly fighters, that's enough to fend off a strike force from a 22,000 ship.

I got 50mm of deck armor and 48 planes on a 10kts hull with a speed of 30kn and 8000nm range for 1925. It wasn´t such a bad design, mind you. A good seaboat etc. but would an Empire like the SAE really build such a small CV? What about prestige? Most other navies will have CVs well beyond 22kts displacement. Wouldn´t a 10kts SAE carrier look somewhat punny?

Btw, I´m not sure if it is really true that one gets more airplanes the more small hulls (instead of large) one has.
I could build eleven 10kts CVs of the design mentioned above and get 528 planes out of it. On the other hand I could easily build eight 13800ts carriers with 70 planes each (but only 20mm splinterproof deck) and end up with 560 planes. Or if I really want that 50mm deck i could go for 8x64 planes for a total of 512. The difference to 528 seems marginal and the larger hulls will have a much better resistance against TT hits.

Quoted

Originally posted by The Rock Doctor
These "jeep carriers" won't be first-rate combat units, but later in life, they'll still make effective escort carriers for convoys, training, ASW work, and so forth. Early on, they can also exercise against each other to develop your anti-carrier doctrine.

I always wanted to know one thing: Where does the term "jeep carrier" come from?

Quoted

Originally posted by The Rock Doctor
After that, step up to an evolving series of medium carriers. I'd be thinking six 15,000 ships, built in pairs a few years apart. A ship of this size can do 31+ knots, carry 50 - 60 aircraft, and mount 2 to 3 inches of deck armor. These would be large enough to carry mixed strike forces and have an offensive role.

Is there a special reason why you want to build pairs all the time? Just curious....

Anyway, thanks for the input.

HoOmAn

The French and Russian governments also note the activities of General Mitchell, but consider the problems of targeting a battleship underway from high altitude to be a factor the good General underestimates. In March 1921, the Russian Black Sea Fleet conducted experiments with aircraft dropping 50kg sacks of ground-up chalk from 3000m on battleships and cruisers underway but not firing AA armament. Many tall white spashes, and much white-colored water resulted.

There were very few white ships however.

Estimating ship speed, wind, and accounting for possible evasive maneuvers remain significant problems, even in the absence of fire from ship AA guns.

Torpedo bombers are felt to be the more effective method of attacking ships, and aerial mines also offer possibilities, if their annoying habit of exploding when they hit water can be stopped. The threat from these aircraft is indeed serious.

The multiple, long sea lanes SAE wishes to protect argue for a large number of hulls, perhaps 7-9, since each can protect fleets/shipping within a radius of 150-250 NM, as aircraft develop, and one or two might be in refit at any given time.

There is indeed no rush to complete that number. Start with one, begin another with lessons learned from the first, and then start them two at a time. Such a program ought to achieve the desired number by the mid-1930s.

The pages of Morskoi Sbornik are filled with heated discussions of the characteristics and roles of escort carriers the size of CLs, scout carriers the size of CAs, and fleet carriers of 18-22ktons, the composition of their air wings, the distribution of them among RF's four major fleets, and their tactics for different types of operation. And all this based on the experience of an uncompleted collier conversion and a single simulated carrier deck.

France is building two experimental carriers on the hulls of Normandie class battleships, to test different elevator designs, and have a simulated flight deck as well. The main factor driving developments seems to be aircraft engine power, and a French-led R&D effort funded by France and Russia to develop more powerful engines.

In both France and Russia, naval aircraft with 400hp engines are entering service, with satisfactory performance so far, in the scout, fighter, and torpedo bomber roles. Such engines allow scouts to take off with large amounts of fuel, in lieu of torpedos/bombs, thus increasing effective scouting range.

"The pages of Morskoi Sbornik are filled with heated discussions of the characteristics and roles of escort carriers the size of CLs, scout carriers the size of CAs, and fleet carriers of 18-22ktons"

Coincidental these are also the displacements I played around.

The Americans got a rather heavy air group out of 15kts on RANGER, IIRC, but they skipped deck armour entirely - to learn the hard way that there could be times where deckarmour is not the worst feature of a carrier.

In 1925 my 15kts designs either offer no great advantage over smaller carriers and are much weaker than full-sized CVs.

Atlantis is also allowed 110,000 tons of carriers under the treaty of Cleito but its carrier fleet is much different from the SAE's. In june 1917 the cruiser Active was completed after she was converted before completion to an experimental aircraft carrier very similar to the HMS Vindictive except that all the 7.5 guns forward were removed leaving her with 3 7.5" (two on each beam aft, one on stern) and 4x4" added. A workshop was placed forward of the existing bridge and a hangar placed aft. A flying off platform was errected forward, on top of the workshop extending almost to the tip of the bow. Aft, a deck was built on top of the hangar extending aft to the aftermost 7.5" turret, and a lift was installed to bring aircraft onto the flight deck. The forward flying off deck was joined to the aft landing deck by a catwalk on the port side. In 1918 the two funnels were trunked together, the remaining 7.5" guns removed and replaced by 4x3" AA, the aft landing deck extended forward and aft and another catwalk was added to starboard. The ship is about to undergo another reconstruction to convert her to a seaplane carrier when her forward flying off deck will be removed one of the aft 4" will be placed forward of the workshop, while her flightdeck aft will be trimed down and the 3" AA guns aft will be repositioned on either side of the hangar and replaced by another aft 4".
In august 1917 the Battlecruiser Evanor was converted in a similar way to the Active, having her 3 forward 12" turrets, 8x5.5" casemates and CT removed and replaced with a flying off deck, two hangars, one forward of the bridge and another aft of the aftermost funnel replacing the aft superstructure. Six 3" AA were added midships on either side of the forward funnels.
The Evanor is due to be removed from service when the Fearless enters service.
In 1918 the Liner Maren was converted to a full length flight deck carrier and renamed Siboney. In her convertion her superstructure was surmounted by a flightdeck that streached nearly the full length of the deck, and 6x3" AA were added. the Siboney is due to be removed from service when the Arrogant enters service
The Arrogant and Fearless are two former Vengeance class BC's cancelled under the Treaty of Cleito and were permitted to be converted to carriers. The biggest problem is the ammount of Atlantis's carrier tonnage alotment used by these two ships each displacing 32,300 tons thus leaving 45,400 tons for new carrier construction and as a result ways of reducing weight are being looked at. Another problem caused by these two ships is that as a result of them being over the 27,000 ton limit to convertions Atlantis must remove two capital ships from service and convert a third to a training ship. This leaves the battlefleet at some disadvantage for some time untill the ships removed from service are able to be replaced by new ships.
It is expected that as a result of the Arrogant class CV's effect on capital ship numbers that these ships will be used more aggressively than their scout style predecessors. As a result of British CV and aircraft inovations, Atlantis has vigorously strived to keep pace technologically and is actively developing torpedo and fighter aircraft for its newest carriers.

Atlantis is looking at building a carrier in the 10,000/12,000 ton range after the Arrogant and fearless are completed. After that who knows?, I have 45,400 tons to play with.

Iberia is still rather sceptical (especially the king) about the whole thing. The two Navarras will commence conversion to experimental carriers in IV/21 and once they are at sea we will see. further construction is unlikely to happen before 1925/26

Bernhard

Given SAEs situation as discribed, what would you build if responsible for the CV building program?

The minimum number of hulls is four: one for each of the main parts of the fleet (there two more known as the Antarctic Fleet and the Eastern Fleet) and one as backup. Even if building those four units up to the limit this would leave me with another 22kts - maybe for two 11kts CV(E)s of which I can deploy one to each of the smaller parts of the fleet.

I also have a possession right in the Atlantic Triangle of my seaways - the island of St. Helena. This strengthens my position but can hardly negate all threads to my ships.

One also has to keep in mind that the carriers of the SAE are in no way meant to operate independantly from the (battle) fleet.

Quoted

Originally posted by HoOmAn

Quoted

Originally posted by The Rock Doctor
These "jeep carriers" won't be first-rate combat units, but later in life, they'll still make effective escort carriers for convoys, training, ASW work, and so forth. Early on, they can also exercise against each other to develop your anti-carrier doctrine.

I always wanted to know one thing: Where does the term "jeep carrier" come from?

I assume American sailors came up with that term as a way of equating some of the escort-carriers' qualities with those of Jeeps - generally simple, easy to mass-produce, small, rugged, useful for many purposes, unassuming, etc. Asking at the US Navy or Aircraft Carriers fora at the warships1.com-boards would probably provide more learned answers - the History and Warfare section at David Newton's board might also be a good place to ask.

A good start would be an HMS Hermes sized carrier, perhaps two. At around 11,000 tons you could get a cheap carrier capable of carrying 25/30 aircraft and use a relatively small ammount of your total tonnage alotment. After this 22,000 tons is used a larger step could be taken, by designing two 15,000 ton carriers similar to the U.S. Ranger with 80+ planes. This leaves you with 52,000 tons used from your total leaving you with 58,000 tons and you already have 4 carriers. With your remaining tonnage you could get a maximum of 4 hulls at 14,500 tons, or three at 19,333. Useing hindsight the 19,300 ton design would be very good, but the smaller designs may be just as good, a good example would be the Japanese Soryu class.

Well Italy, going for long term planning, aims to have 4 aircraft carriers before 1936.

In 1922/23 my conversion carrier will be ready. She is 27,000t, can carry 72 planes, 28knts+ and has quite a bit of armour.

She would be used as an offensive weapon with fast battleships.

Later, i plan to lay down 3x15,000t carriers. These carry 64planes, 29knts+ and have little armour.

They have phenomonal range, 20,000nm@15knts, so they will make good escorts, also their striking power is very respectable.



17inc, when do you plan to scrap your QE aircraft carrier? It is an obvious breach of treaty; some 4,000t over the 27,000t mark.

20 000nm range at 15 knots? For Italian ships? In the 1920s? Just how many laps of the Med are you planning on having these ships doing?

This is the range data for my "Boiler" Nagato:
Range
29,750nm at 12.00 kts
18,307nm at 15.00 kts
11,900nm at 18.00 kts

So Red Admiral's "Coilers" will have a bigger range than my "Boilers". :-)

Walter

I never said that they were for the 1920's. It's fairly common knowledge that Italy wanted to expand from the med. The range also comes in uselful for something else i have up my sleeve....