WI:10,000 Ton Aircraft Carriers

In the London Naval treaty in 1930, a loophole in the Washington naval treaty was closed was closed which meant that Aircraft Carriers of a tonnage no greater than 10000 tons would not be considered Aircraft carriers under the treaty, meaning they wouldn't count toward tonnage limits.

The Japanese were the only power to use this, as they built the Ryujo, a carrier with a displacement of 8,000 t. The ship had stability problems which required rebuilding to solve, raising the displacement to 10,600 tons. However considering the ship had a airgroup of 48 planes when it was built this can barely be considered suprising. This removed it from the bracket it was in, but no one cared.

So my question is this. Presuming the loophole isn't removed in the London Naval treaty, would other countries build similar light carriers? I could see the RN being interested in such vessels for trade protection against surface raiders (Something considered a real threat in the 1930's)


Here is examples of Ships around the same Displacement.

-Independence-class light carrier - 33 Aircraft, 31.5 Knots, 11,000 Tons
-Casablanca-class escort carrier - 28 Aircraft, 20 Knots, 7,800 Tons
-Zuihō-class Light Carrier -30 Aircraft, 28 Knots, 11,443 tonnes
- Colossus class Light Carrier - 31 Aircraft, 25 Knots, 13,200 tons
 
There have been other threads that have posited this, and I have to feel that the answer would be yes. Also, if we take into consideration that everybody lied about their ships displacements, could we eally see 12,000 ton ships like this built?
 
As you said The Ryujo was a total failure. Zuiho-class was pretty good but her airgroup was her only weakness.
That's the critical point with light carrier : the airgroup is too small compare to heavy carrier like Essex-class or Shokaku-class.
So if we considered that the loophole isn't removed frankly i didn't see any nation (except japan) who wants to fill its navy with a ship who has no chance in real fight. Mass-production DD and light cruisers are more valuable especially if you assigned them to trade protection.
 

Ramontxo

Donor
The problem with small carriers is that they move a lot. And if you are restricted to illogical aircrafts, that first land and then stop (yes a pro Harrier and F35-B pun :D) there is a practical limit to how small you can go...
 
How about a CVL built at 9000 tons empty and 10500 tons full of crew, supplies, munitions, POL and Aircraft?
 
How about a CVL built at 9000 tons empty and 10500 tons full of crew, supplies, munitions, POL and Aircraft?

Useless. Maybe she will have great speed but surely no valuable AA defense, ridiculous Airgroup (especially during the pre-WWII period), no hull. At the first air raid (with dive bombers an torpedoes) she will explore the abyss. No it's a waste of money, ressources and manpower
 
Useless. Maybe she will have great speed but surely no valuable AA defense, ridiculous Airgroup (especially during the pre-WWII period), no hull. At the first air raid (with dive bombers an torpedoes) she will explore the abyss. No it's a waste of money, ressources and manpower

She can still be used as an ASW unit on convoy duty or extra CAP to defend the tankers refueling the task force...
 
She can still be used as an ASW unit on convoy duty or extra CAP to defend the tankers refueling the task force...

Destroyer or LightCruiser are better in this role. And because they are cheaper, you can build two or three of them for the cost of one useless 9000-ton carrier ;)
 
She can still be used as an ASW unit on convoy duty or extra CAP to defend the tankers refueling the task force...
Yep, I have to agree on both these counts.

Destroyer or LightCruiser are better in this role. And because they are cheaper, you can build two or three of them for the cost of one useless 9000-ton carrier ;)
Low flying aircraft are smaller and harder to spot, move much faster, can see much farther, and cover vastly more area, than what can be covered by the DD's, and as the SS are mainly operating on the surface, surprising one is much more likely with an aircraft than a DD. One CVL could easily have 12 planes for such work at any given time, and still retain planes in ready mode. I wouldn't say get rid of the DD's entirely, but they do not surpass CVL's.:)
 
Yep, I have to agree on both these counts.


Low flying aircraft are smaller and harder to spot, move much faster, can see much farther, and cover vastly more area, than what can be covered by the DD's, and as the SS are mainly operating on the surface, surprising one is much more likely with an aircraft than a DD. One CVL could easily have 12 planes for such work at any given time, and still retain planes in ready mode. I wouldn't say get rid of the DD's entirely, but they do not surpass CVL's.:)

In that case use aviation-cruiser like refit Mogami-class or Tone-class. Or Better make convoy with DD, aviation-cruiser and two aviation-battleship like Ise-class :D
I'm joking but yes you're right : a plane can do much more than a DD, and it's stealthier. But IMO having light carrier in your convoys is a waste of ressources. Just look at the airgroup of Ryujo for example : in 1942 it counted 16 A6M Zero and 9B5N Kate. What you can do with that ? Nothing. If you want to defend a convoy with that you're in deep shit. Only one heavy carrier (Hiryu for example) can easily overflow your air defense. And don't imagine that you can counter-attack. AA-defense will rekt your planes.
So NO for trade protection it's better to have numerous DD than mass-production 9000-tons carrier. For CAS however that's very good (see the reconquest of the Philippines and the legendray battle of Samar :D)
 
Destroyer or LightCruiser are better in this role. And because they are cheaper, you can build two or three of them for the cost of one useless 9000-ton carrier ;)

10,000 Tons is on the wrong side of too light IMO

Granted an AC like a Swordfish would be fine but lets face it the design would be used for other tasks and not just ASW Escort

One of my 'Darlings' which is often murdered (and rightly so) is that in the early 30s Britain converts the 3 Hawkin Cruisers Effingham, Hawkins and Frobisher into Trade Protection Carriers and 2 of them start the war conducting anti raider and ASW Patrols in the southern oceans.
 
In that case use aviation-cruiser like refit Mogami-class or Tone-class. Or Better make convoy with DD, aviation-cruiser and two aviation-battleship like Ise-class :D
I'm joking but yes you're right : a plane can do much more than a DD, and it's stealthier. But IMO having light carrier in your convoys is a waste of ressources. Just look at the airgroup of Ryujo for example : in 1942 it counted 16 A6M Zero and 9B5N Kate. What you can do with that ? Nothing. If you want to defend a convoy with that you're in deep shit. Only one heavy carrier (Hiryu for example) can easily overflow your air defense. And don't imagine that you can counter-attack. AA-defense will rekt your planes.
So NO for trade protection it's better to have numerous DD than mass-production 9000-tons carrier. For CAS however that's very good (see the reconquest of the Philippines and the legendray battle of Samar :D)
I think we are thinking about two different situations here, I am thinking N Atlantic convoy lanes being protected/patrolled by CVL's from submarines, whereas I think you are taking more of a global view (which is probably better overal, but may just make folks overlook the alternatives where such would be worthwhile). Where the threat is mainly limited to submarines (and possibly surface raiders --- desguised or otherwise), the CVL should prove more than good enough. Where enemy aircraft (either land or carrier based) are a likely threat, then you need to send in the CV's, or not send you merchantmen.:)
 
Destroyer or LightCruiser are better in this role. And because they are cheaper, you can build two or three of them for the cost of one useless 9000-ton carrier ;)

Useless? I think not. Pre-war, the RN were worried about commerce raiders, which could cause damage to British trade. A light carrier based on the Leander Cruiser hull, with a 20 plane airgroup which at the outbreak of could be 12 Hawker Ospreys for fighters and ASW, and 8 Blackburn Shark torpedo bombers is quite adequate. The planes are obsolete, but as all they need to do is locate the commerce raider and launch a strike to slow it so the cruisers can finish it they are adequate. Of course, after 1940, they could be used in more hostile waters, but more likely they would be used for Anti-submarine patrols. And as for cost, less armoured plate is being used (This makes them next to dead if threatened by a decent attack.) Their sole armament would be a few dual purpose guns. They wouldn't cost more than 1.25x a light cruiser.
 
10,000 Tons is on the wrong side of too light IMO

Granted an AC like a Swordfish would be fine but lets face it the design would be used for other tasks and not just ASW Escort

One of my 'Darlings' which is often murdered (and rightly so) is that in the early 30s Britain converts the 3 Hawkin Cruisers Effingham, Hawkins and Frobisher into Trade Protection Carriers and 2 of them start the war conducting anti raider and ASW Patrols in the southern oceans.

The challenge with ATLs is always plausibility, yet it seems to me more plausible than OTL, that the 'Improved Birmingham Class of Cruisers were converted to CVLs (through-deck-cruisers) in the twenties - rather than OTL where the Vindictive was converted back to a cruiser in 1923-25.

With the experience of the CVL, it brings forward on the one hand a replacement like the Colossus Class earlier, and on the other Mercantile Hull conversion Escort Carriers.
 
That's the critical point with light carrier: the air group is too small compare to heavy carrier like Essex-class or Shokaku-class.
Isn't that a bit like saying that cruisers guns are too small compared to battleships guns so obviously they're useless? I agree that you're not going to see people rushing out to build all 10,000 ton aircraft carrier fleets but they do have a place if used properly.


Useless. Maybe she will have great speed but surely no valuable AA defence, ridiculous air group (especially during the pre-WWII period), no hull. At the first air raid (with dive bombers an torpedoes) she will explore the abyss. No it's a waste of money, resources and manpower.
Really? The US Navy seems to have disagreed with you considering that they built something like 80-odd escort carriers in roughly the proposed displacement range during WWII. The Casablanca- and Commencement Bay-class carriers could carry an air group of around 30 aircraft and had defensive armaments of 16 40mm Bofors guns and 20 20mm Oerlikon cannons, and 2 5-inch guns, 36 40mm Bofors guns and 20 20mm Oerlikon cannons respectively. Granted these were built in WWII but technologically there wasn't anything stopping them from being built earlier I believe.

As I said earlier obviously they're going to carry fewer aircraft and armaments than light fleet carriers or the fleet carriers, plus potentially have somewhat lesser survivability due to displacement restrictions so you have to use them in the proper manner. The clue is in the name escort carrier, so that's what you use them for - escorting fleets of ships, be they military or cargo convoys, that require protection from submarines or aircraft but which aren't required to face the main force of the enemy or to help patrol a wider area.


Destroyer or light cruisers are better in this role. And because they are cheaper, you can build two or three of them for the cost of one useless 9000-ton carrier. ;)
Wait, you want to use light cruisers for anti-submarine work? Yeah I'm sorry but that just strikes me as crazy. Do you have any figures for the costs of a light cruiser compared to an escort carrier as I would be very surprised if the latter was more expensive than the former. You've also got the bottlenecks of manufacturing the heavy guns and fire control systems needed for light cruisers. As others have said aircraft operating from carriers can cover and patrol a lot more ground in a much smaller time than a single cruiser.
 
The challenge with ATLs is always plausibility, yet it seems to me more plausible than OTL, that the 'Improved Birmingham Class of Cruisers were converted to CVLs (through-deck-cruisers) in the twenties - rather than OTL where the Vindictive was converted back to a cruiser in 1923-25.

With the experience of the CVL, it brings forward on the one hand a replacement like the Colossus Class earlier, and on the other Mercantile Hull conversion Escort Carriers.

The Birmingham class are too light by about 4-5K tons IMO - and while probably fast enough - the design leap from Birmingham to Hawkins is too great


An Earlier Colossus? So a 1939 light Pattern Fleet carrier :D
 
The Birmingham class are too light by about 4-5K tons IMO - and while probably fast enough - the design leap from Birmingham to Hawkins is too great


An Earlier Colossus? So a 1939 light Pattern Fleet carrier :D

But - I didn't say 'Birmingham class', I was agreeing with you the ships that made up the 'Improved Birmingham Class are:
- HMS Vindictive (ex-Cavendish), 9,770 tons, launched 1.10.17,
- HMS Effingham, 9,550 tons, 28.8.19,
- HMS Frobisher, 9,860 tons, 8.6.21 and
- HMS Hawkins, 9,800 tons, 20.3.20

In OTL, just Effingham was lost - 25.5.40, with the others scrapped in the late forties.
 
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