JMSDF CVH helicopter carrier

[Triton]

From Ronnie Serrano on the "Project Terminated" page on Facebook:

Source:
https://www.facebook.com/photo.php?fbid=876967599032670&set=gm.646696872124265&type=1&theater

Another surprise and rare find I've ran across today is that Japan proposed a helicopter carrier called the CVH which was planned back in early-1960's. There were two variants of the CVH like the CVH-A which was an ASuW carrier capable of carrying 18 helicopters mostly the SH-3J's and four S-2 Trackers. Another one was the CVH-B which was pretty much pure helicopter carrier which carried only 18 helicopters. However, in 1961, the Japanese decided to go with the CVH-B variant instead since it was cheaper and easier to maintain. Despite that, U.S and the Japanese Diet was against the helicopter carrier proposal because pacifist constitution and concerns that a arms race might start up in the region. So the CVH-B project was dropped and decided to developed a helicopter destroyers instead like the Haruna class instead.

 

[JohnR]

The CVH-A doesn't make a lot of economic sense. Carrying four S2 Trackers would surely require Cats and Traps; which could hardly be justified for such a small number of aircraft.

 

[Triton]

The CVH-A doesn't make a lot of economic sense. Carrying four S2 Trackers would surely require Cats and Traps; which could hardly be justified for such a small number of aircraft.

Article 9 of the Japanese Constitution has been interpreted to mean that Japan cannot hold offensive military weapons--this has been determined to mean that Japan cannot have ICBMs, nuclear weapons, aircraft carriers, or bomber fleets. Japan has to go out of its way to create helicopter-carrying destroyers to be used for anti-submarine warfare.

Source:
http://en.wikipedia.org/wiki/Article_9_of_the_Japanese_Constitution

 

[Abraham Gubler]

The CVH-A doesn't make a lot of economic sense. Carrying four S2 Trackers would surely require Cats and Traps; which could hardly be justified for such a small number of aircraft.

It makes good operational sense. 12 Sea Kings and 4-6 Trackers is what a typical 1960s 15 knot convoy needs for ASW protection (plus 4-6 frigates) to defend against Type XXI type submarines (Whisky, Foxtrot). So a single anti submarine carrier with such an air wing could provide the air support for the convoy. Also I doubt the cost in Yen, tonnes and crew of the catapult and arrestor gear is so significant. Especially to support a Det of Trackers.

 

[Abraham Gubler]

More info on the 1960s CVH from:


http://www.globalsecurity.org/military/world/japan/cv-newcon.htm

Japan is not, in principle, allergic to operating fixed wing aircraft from ships, unlike the nuclear allergy. Vice Admiral Yoji Koda noted that in the late 1950s "the JMSDF Maritime Staff Office (MSO) in Tokyo developed a plan for two variants: “CVH-a,” of twenty thousand tons, with eighteen helicopters and four to six S-2 fixed-wing maritime patrol aircraft; and “CVH-b,” of ten thousand tons, with eighteen helicopters. It was decided that CVH-b would be more suitable for the JMSDF. .... CVH construction was not included and was never discussed again in later years. This was the first demise of the JMSDF helicopter carrier". Instead, a series of helicopter escort ships was started, culmnating half a century latter in the 22DDH.

 

[Abraham Gubler]

Here is some more information on the CVH-A and CVH-B proposals from:

http://ja.wikipedia.org/wiki/%E6%B5%B7%E4%B8%8A%E8%87%AA%E8%A1%9B%E9%9A%8A%E3%81%AE%E8%88%AA%E7%A9%BA%E6%AF%8D%E8%89%A6%E5%BB%BA%E9%80%A0%E6%A7%8B%E6%83%B3

Translated by Google and then translated again by me.

The CVH-B was to provide protection to a convoy from Type XXI fast diesel submarines. To provide protection against nuclear submarines with higher speed than Type XXI submarines additional air assets were required. These assets were both close support aircraft and helicopter screens forward and to both sides of the convoy. To meet this requirement the larger CVH-A was needed with a displacement of 23,000 tons and an air wing of 18 HSS-2 Sea Kings and six S2F Trackers.

CVH-B
Displacement: 8,000 tons light, 11,000 tons standard, 14,000 tons full
Length: 166.5m overall, 160m waterline, 155mm flight deck
Beam: 26.5m flight deck (maximum), 22m waterline
Draft: 6.5m
Propulsion: two boilers, two steam turbines, two shafts producing 60,000 hp in total
Speed: 29 knots
Armament: four Mk 33 twin 76mm.
Sensors: OPS-1 air search radar, OPS-3 surface search radar, two Mk 63 directors, AN/SQS-4 sonar
Aircraft 18 HSS-2 Sea King.

The CVH-B was designed in 1959 and was to use the propulsion systems of the “35DDG” class (JDS Amatsukaze). The flight deck was to have three landing spots and two elevators of 17mx8m with the aft elevator on the deck edge. Hangar was to be 112.5m long and 22m width (maximum) and able to store all 18 helicopters. In the hangar a sliding, fire proof door is positioned 4m aft of the centre for damage control.

Construction costs were estimated at 10 billion yen with Japan paying 80.5% and the USA the 19.5% (via aid). 27 HSS-2 Sea Kings were also to be purchased to provide the air wing with Japan paying 47.8%, and the USA 52.2%. Total cost of the program was to be paid 62.8% by Japan and 37.2% by the USA. The carrier was to be the centre of a task force with 1 x CVH, 1 x DDG, 2 x DD and 3 x DDK (DE or FF).


In 1960 it was decided to built the fist CVH-B at Chogi but by 1961 it was cancelled. Reasons for the cancellation were economic with pressure provided by the high cost of the 35DDG which reached 9.8 billion yen.

 

[Triton]

Thank you for the information, Abraham.

 

[Grey Havoc]

The 22DDH can trace it's origins all the way back to the JMSDF's "CVH-a" concept of the 1960's. Some interesting background on it here, as well as on the "CVH-b" concept which one could say is the ancestor of the Hyūga class DDHs.

 

[Abraham Gubler]

Thank you for the information, Abraham.

No problem, thanks for posting about the ship in the first place I had never heard of it and its right in the middle of my interest area.

 

[Hood]

A couple of early Hyuga concepts dating from circa 2001.

 

[Bgray]

You know that first concept looks like some concepts from the 1970s--what was the point of the full-width deck house? I'm assuming it was to save money/space/complexity by eliminating the need for a lower hanger deck and thus the need for elevators, at the cost of reducing the helicopter complement.

 

[TomS]

You know that first concept looks like some concepts from the 1970s--what was the point of the full-width deck house? I'm assuming it was to save money/space/complexity by eliminating the need for a lower hanger deck and thus the need for elevators, at the cost of reducing the helicopter complement.

Yeah, it's very reminiscent of one of the Flight Deck Spruance designs that was floated.

One of the less obvious drawbacks of the design is that the door on the front of the island can turn the hangar into a wind tunnel if you open it at high speed.

 

[Yellow Palace]

You know that first concept looks like some concepts from the 1970s--what was the point of the full-width deck house? I'm assuming it was to save money/space/complexity by eliminating the need for a lower hanger deck and thus the need for elevators, at the cost of reducing the helicopter complement.

At this point, I've a strong feeling that it's a natural stage in the evolution of the through-deck aviation ship. The requirements people say 'we don't need an aircraft carrier, we just want lots of helicopters', the engineers come up with flight decks fore and aft of a full-width deckhouse, then the operators realise that it would all work a lot better if you only had one flight deck, a small deckhouse, and the hangar below deck.

The Royal Navy has done it twice, the US Navy has done it on paper, evidently the Japanese Navy (duck test!) has done it. I'd be surprised if the Soviet and Italian navies hadn't done it too.

 

[Hood]

Indeed Italy's first attempt at a 'through-deck cruiser' was a weird layout, an island but plenty of weapons cluttering the deck. https://www.secretprojects.co.uk/threads/the-first-trieste.32154/#post-357413

 

[TomS]

Indeed Italy's first attempt at a 'through-deck cruiser' was a weird layout, an island but plenty of weapons cluttering the deck. https://www.secretprojects.co.uk/threads/the-first-trieste.32154/#post-357413

Early VTOL carriers were so weird. It's like designers forgot that half the point of the flight deck is the deck park.

 

[cattalonX]

 

[Tzoli]

Ahh thd 1960's 8.000ton Helicopter Carrier design of the JMSDF, basically the first carrier design of Japan after WW2.
Artist's impression of the proposal:

 

[TomS]

View attachment 686554View attachment 686555View attachment 686556

Lovely. Are these official drawings?

The hangar packing arrangement of 18 Sea King seems really optimistic, but otherwise this looks like a plausible design. Could do with the bow being plated in a la the US Hurricane bow (some IJN design holdover influence here?). And four twin 3-inch/50s is pretty anemic for self-defense, but there were really no other options at the time.

 

[cattalonX]

Not

View attachment 686554View attachment 686555View attachment 686556

Lovely. Are these official drawings?

The hangar packing arrangement of 18 Sea King seems really optimistic, but otherwise this looks like a plausible design. Could do with the bow being plated in a la the US Hurricane bow (some IJN design holdover influence here?). And four twin 3-inch/50s is pretty anemic for self-defense, but there were really no other options at the time.

Not official drawings
These drawings are from a magazine published by an Japanese engineer（岡田幸和） in the mid90s

 

[Kat Tsun]

anything on his size or dimensions? he seems smaller than even the sea control ship, but that might just be the three vice two SH-3 spots

 

[TomS]

anything on his size or dimensions? he seems smaller than even the sea control ship, but that might just be the three vice two SH-3 spots

This is CVH-B. See post #6 for specs.

 

[Kat Tsun]

wow that's shockingly forward thinking for the time tbh

if it had been built it's almost trivial to imagine this being modernized through the 1980's for use with AV8s or something

also 29 knots holy moly that's fast for a tiny cv of any era

 

[TomS]

wow that's shockingly forward thinking for the time tbh

if it had been built it's almost trivial to imagine this being modernized through the 1980's for use with AV8s or something

also 29 knots holy moly that's fast for a tiny cv of any era

It's essentially a steam-powered SCS with 50% more power, in keeping with the very first iteration of US SCS designs c. 1970. The USN wasn't interested in this type of ship much earlier mainly because it had enough WW2 CVS with S-2s, while Japan had scrap metal.

The main layout change to me is that the Japanese ship keeps the island midships, which means they had to bump the flight deck out to get a helo spot near the center of motion, while the eventual USN SCS design pushed the island aft and had room for helos near the center of motion without a wider deck.

 

[Teapot]

For anyone still interested in the topic of this ship, I've recently completed an interpretation of it based on assorted information:

 

[GK Dundas]

What seemed to be missed a lot of the time what makes a carrier important to task group or to an escorted convoy. Isn't just the Carrier's contribution to it's defence but the ability to provide maintenance to the escort's helicopters which are arguably a ship's main asw battery.

 

[NH 17]

Love the CVH-B design. Although the US Navy's Sea Control Ship design came 15 years later, there are many similarities, including their general characteristics, size, function and aircraft load.

The JMSDF managed the DASH program better than the USN, but still a drone or two per escort was no match for fielding a dozen Sea Kings and (potentially) a half dozen Harriers. The Canadians had mightily placed Sea Kings on Saint Laurent's in the mid sixties, but that was just one aircraft working from the tiny deck of a 2260 ton, 366'/111.5m ship. Wasps flew from Leander's, which was fantastic, but really a fairly austere system. Blake and Tiger shipped four Sea Kings in what might be described as a limited capability for a huge expense. Italy's Andrea Dorias and Vittorio Veneto seemed a better deal. Maybe the Soviet Moskva as well. LAMPS SH-2Ds were coming online in the USN from 1972, which was great, if overdue. CNO Zumwalt's plan was to field a ship that the JMSDF had conceived and might have employed a decade or so earlier. Multiple aircraft could prosecute different contacts from a more stable platform, and then could return to be serviced in a better equipped hanger. In the JMSDF case, there was the ghost of world war guilt, and reportedly DDG cost over runs that sank their plans (Anyone without fluency in Japanese and access to JMSDF archives can only speculate). In the SCS case it was a tight budget (isn't it always?) and seemingly a fear from the carrier guys that these little ships would siphon away money and support from their big and sexy CVNs. We suffer the same today. Why have frigates when there are Aegis DDGs? Why field AIP SSs when we have SSNs?

The Spanish Armada operated a modified SCS, Principe de Austurias for a quarter century. I would be interested to know more of their experience. The same could be asked of the Royal Thai Navy's Chakri Naruebet, but she seems to be a pier queen that gets turned around every now and then.

 

[GK Dundas]

Love the CVH-B design. Although the US Navy's Sea Control Ship design came 15 years later, there are many similarities, including their general characteristics, size, function and aircraft load.

View attachment 694266The JMSDF managed the DASH program better than the USN, but still a drone or two per escort was no match for fielding a dozen Sea Kings and (potentially) a half dozen Harriers. The Canadians had mightily placed Sea Kings on Saint Laurent's in the mid sixties, but that was just one aircraft working from the tiny deck of a 2260 ton, 366'/111.5m ship. Wasps flew from Leander's, which was fantastic, but really a fairly austere system. Blake and Tiger shipped four Sea Kings in what might be described as a limited capability for a huge expense. Italy's Andrea Dorias and Vittorio Veneto seemed a better deal. Maybe the Soviet Moskva as well. LAMPS SH-2Ds were coming online in the USN from 1972, which was great, if overdue. CNO Zumwalt's plan was to field a ship that the JMSDF had conceived and might have employed a decade or so earlier. Multiple aircraft could prosecute different contacts from a more stable platform, and then could return to be serviced in a better equipped hanger. In the JMSDF case, there was the ghost of world war guilt, and reportedly DDG cost over runs that sank their plans (Anyone without fluency in Japanese and access to JMSDF archives can only speculate). In the SCS case it was a tight budget (isn't it always?) and seemingly a fear from the carrier guys that these little ships would siphon away money and support from their big and sexy CVNs. We suffer the same today. Why have frigates when there are Aegis DDGs? Why field AIP SSs when we have SSNs?

The Spanish Armada operated a modified SCS, Principe de Austurias for a quarter century. I would be interested to know more of their experience. The same could be asked of the Royal Thai Navy's Chakri Naruebet, but she seems to be a pier queen that gets turned around every now and then.

Ahh you mean the Thai Royal yacht where Thai Royal family go to unwind and chill while sitting out the next military coup.

 

[GK Dundas]

Actually the Spanish built SCS Principe de Austurias strikes me as very interesting topic .
Amongst her other claims to fame is she could carry an air group of some 37 aircraft. More then her British counterparts Invincible and her Sisters. In spite of their larger size.

 

[Archibald]

The JMSDF managed the DASH program better than the USN, but still a drone or two per escort was no match for fielding a dozen Sea Kings and (potentially) a half dozen Harriers. The Canadians had mightily placed Sea Kings on Saint Laurent's in the mid sixties, but that was just one aircraft working from the tiny deck of a 2260 ton, 366'/111.5m ship. Wasps flew from Leander's, which was fantastic, but really a fairly austere system. Blake and Tiger shipped four Sea Kings in what might be described as a limited capability for a huge expense. Italy's Andrea Dorias and Vittorio Veneto seemed a better deal. Maybe the Soviet Moskva as well. LAMPS SH-2Ds were coming online in the USN from 1972, which was great, if overdue.

The Spanish Armada operated a modified SCS, Principe de Austurias for a quarter century. I would be interested to know more of their experience. The same could be asked of the Royal Thai Navy's Chakri Naruebet, but she seems to be a pier queen that gets turned around every now and then.

No love for the Jeanne d'Arc ? https://en.wikipedia.org/wiki/French_cruiser_Jeanne_d'Arc_(R97)

 

[NH 17]

An inexcusable oversight.

 

[Archibald]

I was half-joking. Was wondering how did the Jeanne compared to the italian helicopter cruisers and Moskva ?

 

[H_K]

Actually the Spanish built SCS Principe de Austurias strikes me as very interesting topic .
Amongst her other claims to fame is she could carry an air group of some 37 aircraft. More then her British counterparts Invincible and her Sisters. In spite of their larger size.

Take that number with a big pinch of salt. That was not an operational number but rather the maximum hangar & deck capacity.

The USN plan for SCS was 19 aircraft (14 Sea King, 3 Harriers and 2 Sea Sprite) and that is much closer to the real world air groups that the Spanish flew (18-21 aircraft max, of which 8-10 Harriers, 7-9 Sea King and 2-4 AB 212.

 

[TomS]

Actually the Spanish built SCS Principe de Austurias strikes me as very interesting topic .
Amongst her other claims to fame is she could carry an air group of some 37 aircraft. More then her British counterparts Invincible and her Sisters. In spite of their larger size.

Take that number with a big pinch of salt. That was not an operational number but rather the maximum hangar & deck capacity.

The USN plan for SCS was 19 aircraft (14 Sea King, 3 Harriers and 2 Sea Sprite) and that is much closer to the real world air groups that the Spanish flew (18-21 aircraft max, of which 8-10 Harriers, 7-9 Sea King and 2-4 AB 212.

And that figure is right in line with the post-Falklands refit capacity of the Invincibles at 9 Harrier and 12 Sea King/Merlin.

 

[Hood]

I've moved out the lengthy Jeanne d'Arc/Mascura discussion to here.