French nuclear-powered amphibious assault ship (PH 75/PA 75)


Donald McKelvy
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14 August 2009
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PH 75/PA 75 was a military development program in France aimed at designing a nuclear-powered amphibious assault ship during the 1970s for the French Navy (Marine Nationale). Two ships were planned. Design work was never completed by the time the project was canceled.

In 1970, with Arromanches fast approaching the end of her active life, studies were undertaken to provide for a replacement. A number of possible designs were produced, all of which shared the 55,000shp steam plant of the F 67 frigates, a through deck for helicopters, and a uniform armament of four 100mm mountings.

The first three versions displaced 20,000-22,000t, had a waterline length between 187m and 200m and a beam of 28m, with a maximum speed of 27kts. The first two versions incorporated a docking well aft, 40-50m long and 14m wide. The docking well of the first variant could accommodate four LCMs (26t), while that of the second variant, which was longer and higher, could accommodate two LCMs and two CTMs (56t). (The LCM has a cargo capacity of 30t, and the CTM of 90t, and both can carry a light or medium tank).

The flight deck configuration of the first variant was clearly influenced by the US Navy's Iwo Jima class; the deck itself was rounded off at its forward edge, and side lifts were staggered to port and starboard. In the second variant the flight deck had a broad centre section not unlike that of the US Navy's CVAs, with lifts on either side of the island to starboard incorporated into the overhang. A similar arrangement was adopted in the third variant, which dispensed altogether with the docking well.

These first three variants all had a hangar of about 90m length with a capacity of 8 Super Frelons and 18 Lynx. There was accommodation for 600 men and their equipment, together with light vehicles.

The fourth variant was a smaller vessel, 170m x 25m, with a displacement of 15,000t, and a consequent increase in speed to 28.5kts. Flight configuration was similar to that of Clemenceau, with a centreline lift forward and a side lift to starboard, aft the island. Helicopter capacity was reduced to seven Super Frelons and 16 Lynx, and troop capacity to 450.

In the event none of these designs was proceeded with, but they served as the basis of an even more ambitious project, PH 75. Similar in conception, size and configuration to the third variant of the 1970 designs, PH 75 was to have nuclear propulsion to give her unlimited range for distant intervention. Like Jeanne d'Arc, she would be able to assume the ASW role as an alternative to that of amphibious assault, and was also designed for disaster relief. She was, therefore, given extensive hospital facilities consisting of three main wards, an X-Ray ward, an intensive care ward, an infectious diseases ward, two dental surgeries and a laboratory.

In the intervention role she would carry a special landing force of units from the Forces Terrestres d'Intervenntion (FTI) and their supporting air units (CAFI), plus a Helicopter Movement Command Centre. 1000 troops could be accommodated in designated quarters, with a further 500 in supplementary spaces in the hangar.

The ship would embark Super Frelon and Lynx helicopters in the ASW role, or Puma helicopters for the assault mission. Hangar dimensions were 84m x 21m x 6.5m and there were two side lifts each with a capacity of 15t. There was one fixed and one mobile crane, and extensive helicopter support facilities including workshops, munitions-handling rooms, magazines, and fuel tanks for 1000m3 of aviation fuel.

PH 75 was to be fitted as a command ship, with an action information centre, a communications centre, an ASW centre and an amphibious operations centre. She would carry 1250t of FFO for refuelling escorting warships. As with other French nuclear-powered vessels there were emergency diesel propulsion units capable of powering the ship for 3000nm at 18kts.

PH 75 was originally intended to complete in 1981, but financial problems delayed construction, and the design has been successively re-designated PA 75, PA 78, PA 82, and now PA 88. The change in classification from 'PH' (Porte-Helicopteres) to 'PA' (Porte-Aeronefs) indicates an intention to provide for the embarkation of VTOL aircraft. It now seems likely, however, that if this ship is built at all it will be as a replacement for Jeanne d'Arc, and that she will not be completed before 1990.


Displacement: 16,400t standard 18,400t full load

Dimensions: 682ft oa x 87ft wI, 157ft fd x 21ft
208.0m x 26.4m, 46.0m x 6.5m

Machinery: 2-shaft nuclear: 1 CAS-230 reactor, 2 turbo-reduction-condenser groups
65,000shp = 28kts; 2 AGO standby diesels

Armament: 2 Crotale SAM (2x8), 2-100mm (2xl), 2 Sagaie, 10-25 helicopters

Sensors: Radar DRBV-26, DRBV-51, DRBC-32; sonar DUBA-25

Complement: 890 (+ 1000 troops)


Authors: John Jordan ( Belgium, France, Netherlands )

Line Drawings: Przemyslaw Budzbon – with Mark Twardowski


Date: 1983 – © 1983 Conway Maritime Press Ltd


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I'm somewhat surprised that they didn't try to revive the program during the second half of the 1990's. Or even now.
Grey Havoc said:
I'm somewhat surprised that they didn't try to revive the program during the second half of the 1990's. Or even now.

They had a bad experience with the Charles de Gaulle (not to mention money shortages), so I doubt anybody would have wanted to try again:
True enough, at least for the nineties. Maybe they should have cancelled the Charles de Gaulle before it was laid down, and gone with this proposal instead. From what is known about it, it looks like it was a better thought out, and probably more realistic, design.
Certainly Wikipedia is often wrong, but they cite a French government source for the history of delays:

There is no denying that the ship had a very difficult history before it was completed. So if the question was "why didn't the French navy build something similar?" it seems like de Gaulle is a good answer.
It all boiled down to the old Foch / Clemenceau twins. It sounded logical to have a similar pair of CDGs - and that was the plan from 1990 to 2005 and the move toward CVF.
The money, however, was clearly never there. I can tell ( from a pile of aviation magazines and scrapbooks) that the varied governments kicked the can down the road, balking on costs. The CdG was being build, Clemenceau was withdrawn, Foch sold to Brazil and... nothing happened. The twin never materialized.
"Difficult history" (my words) includes financial problems. And when you say "steep learning curve" I interpret that to mean "technical difficulties that led to higher than expected costs." Seems like we are agreeing here.

But I don't know why you automatically assume that after so many problems with building the first one they could have built a second one on time and budget.
On a related note, has anyone heard whether the French government is currently funding a R&D program for a dedicated carrier/large ship reactor?
[edit - deleted post - Admin]

I thought that the PH75 project was meant to compliment what became the Charles de Gaulle, not be an alternative?

EDIT: Ah, I see where I may have been misunderstood. In my second post on this thread, I was talking about (and linked to) the 1985 Ader Clement CV proposal.
Thread revival!

Does anyone have any detailed information on the developments that flowed on from the PH75/PA75? I am referring here to the PA-78, PA-82 and PA-88 concepts (assuming these are the correct terms).

I have seen the attached drawing used in relation to the PA-78 but have no confirmation of this and also no details.


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That drawing looks like nothing more than a crude mod of the hypothetical PA-76 "What if" drawn by Bager1968 in another forum.

PA-78, PA-82 and PA-88 were probably nothing more than budgetary placeholders indicating when the carrier was expected to be ordered. The numbering doesn't necessarily imply any evolution in the basic concept or design.

For more on the PA-76 and PA-79 "What If", see here:
I wouldn't be surprised if it was a fake (and implied such in my last post). I have seen the designation I used in a number of places though and wanted to see if thre was any details behind them. They may well be nothing more than "placeholders" as you suggest.

Does any one know if there were any conventional CV (i.e. non helicopter/non Harrier style) variants/derivatives of the PH75/PA75?
I wouldn't be surprised if it was a fake (and implied such in my last post). I have seen the designation I used in a number of places though and wanted to see if thre was any details behind them. They may well be nothing more than "placeholders" as you suggest.

Does any one know if there were any conventional CV (i.e. non helicopter/non Harrier style) variants/derivatives of the PH75/PA75?
Briefly mentioned in the Australian Cabinet papers relating to the acquisition of, then Britain's decision to retain, Invincible is a reference to a conventionally powered derivative of CdG being investigated as an alternative, including its potential to operate the RAAFs F/A-18s. With PM&C being firmly against any carrier and the economy nose diving into the worst recession in a generation there was zero chance of it happening, but the reference was interesting and I wonder if there is any data available on this option and whether it may have been related to some of the schemes mentioned in this topic.
Basically the "PA-" numbering sequence for French carriers is kind of a mess. It mixes number designs and years.

For example, PA1 to PA4 were Béarn derivatives, not in 1901 or 1904 but in 1928. Yet PA28 design was from... 1946, and called Clemenceau.
Then, back to year numbering with PA54 in 1954 (Clemenceau) and PA55 Foch (in 1955) PA58 & PA59 Verdun (45 000 tons cut to a 35 000 tons Clemenceau clone in the hope of getting funding). PH75 was related to 1975, yet PA75 lasted into 1980.
In the end the numbering makes as much sense as Su-27 derivatives (the horror, the horror).
I'm not surprised to see CdG considered in the australian paper. Well after the RN got out of the carrier game the one and only and unique alternative for large CATOBAR carriers was France. This doesn't mean the CdG is a good bargain. Whatever its qualities or flaws, nuclear power by itself makes things even harder.

Basically it a shame a conventional carrier couldn't be proposed out of an "uprated Foch / non-nuclear CdG" - Agosta / Scorpène style. It worked very well for SSK with the Scorpènes - developed from the last Agostas, borrowing some tech from Rubis SSN.
Then again, Navantia 25 000 tons CATOBAR and US CVV atempts were not successfull. At all.
I suspect the conventionally powered CTOL carrier proposal was more an effort to demonstrate the capability was unaffordable than a serious option. Air Staff and Dept Prime Minister and Cabinet were opposed to the acquisition of any type of carrier, the argument being the Harrier was inferior to the Skyhawk and F-5 Tiger, therefore not worth having, sonar buoys were more effective than dunking sonar, therefore no need for Sea Kings, with Harriers and Sea Kings not required and CTOL carriers too expensive, there was no justification for the acquisition of a helicopter carrier.
This is a little confusing. Volkodav, I believe the time period you are referring to is ~1980? At that time CdG didn’t exist in any form.

In addition, it seems that a CTOL option was very quickly discarded as “a CTOL aircraft carrier design of suitable size was not available”.

So I struggle to see the connection with any F/A-18 capable French carrier related to CdG. Perhaps PH-75 was in the mix as a helicopter-only or STOVL carrier, but it is not mentioned and it seems that the candidates considered were a US LPH derived from SCS, Invincible and Garibaldi.
The exact words in the document (from 1982) are as follows:

Mention of desire for carrier to be able to take F/A-18s - I believe this refers more to a US design though:


Later in the same document, a conventional powered version of a French Carrier, though also note the mention of operating the same aircraft as the Air Force (presumably F/A-18s):

Yes that was the document I was referring to, reading it almost made my eyes bleed, the total ignorance of so called professionals advising parliament was very disturbing.

The professional press of the day had a better idea about defence capabilities than senior public servants who were meant to be defence procurement experts. I understand hindsight colours views of past decisions, hence the value of reading declassified official papers, but reading them side by side with industry and expert publications shows the specialist magazines were closer to reality that the powers that be.

Unfortunately there are still a great many closed minded, ill informed, or even willfully ignorant people working for government, hence my recent escape back to industry.
For the record:
- PH75 become PA75 around 1980
- Yet Charles de Gaulle wasn't started until February 1986

This mean that the tidbit posted by GTX, which mentions 1982-83, is right in the middle - between the PH75-PA75 transition in 1980 and CdG getting started in 1986.
The tonnage shown (35 000 to 40 000 tons) is right between Foch and CdG.

It is also possible non-nuclear, "upgraded Foch / pre-CdG" were considered before 1986, if only for the sake of making them less expensive. Think PA58 Verdun.

There is a continuity between PA54 (Clemenceau) PA55 (Foch) PA58 Verdun (45000 tons) PA59 (back to 35000 tons Foch clone to get it funded) and PA75 / CdG (even if nuclear). Don't forget, because of naval shipyards limitations, the CdG is essentially a Foch hull form pushed to its extreme limits, nuclear power included.


I've recently red an intriguing press article about CdG crew being very badly hit by COVID.

The article explained that, in order to pack K-27 submarine nuclear reactors, longer catapults (75 m vs 51 m) and enough Rafales inside 45 000 tons / much improved Foch hull form, what had to be sacrificed (something HAD to be...) was crew accomodations.
Basically CdG crew quarters are pretty bad by 2020 standards. Think 1980 Forrestal, really, and smaller. They explained that the 1980-90's generation presently aboard the ship wants more privacy and more comfort that the elders. Smartphones and things like that doesn't help.
This was already an issue before COVID and seems to make recruitment for CdG harder than for more recent ships like the Mistral-class or the Horizon frigates. The more up-to-date ships enter service, the least CdG cramped crew quarters attractive.
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