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Author Topic: French nuclear-powered amphibious assault ship (PH 75/PA 75)  (Read 5099 times)

Offline Triton

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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.

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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.

Specifications

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)

Source:   ALL THE WORLD’S FIGHTING SHIPS – PART 1: THE WESTERN POWERS

Authors:   John Jordan ( Belgium, France, Netherlands )

Line Drawings:   Przemyslaw Budzbon – with Mark Twardowski

Publisher:   CONWAY MARITIME PRESS

Date:   1983 – © 1983 Conway Maritime Press Ltd
« Last Edit: July 29, 2009, 11:04:48 pm by Triton »

Offline Grey Havoc

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Re: French nuclear-powered amphibious assault ship (PH 75/PA 75)
« Reply #1 on: July 25, 2011, 01:05:36 pm »
I'm somewhat surprised that they didn't try to revive the program during the second half of the 1990's. Or even now.

Offline blackstar

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Re: French nuclear-powered amphibious assault ship (PH 75/PA 75)
« Reply #2 on: July 27, 2011, 02:34:11 pm »
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:

http://en.wikipedia.org/wiki/French_aircraft_carrier_Charles_de_Gaulle_%28R91%29


Offline Grey Havoc

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Re: French nuclear-powered amphibious assault ship (PH 75/PA 75)
« Reply #3 on: July 28, 2011, 08:11:56 am »
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.
« Last Edit: July 28, 2011, 08:14:21 am by Grey Havoc »

Offline blackstar

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Re: French nuclear-powered amphibious assault ship (PH 75/PA 75)
« Reply #4 on: July 28, 2011, 03:29:10 pm »
Certainly Wikipedia is often wrong, but they cite a French government source for the history of delays:

http://www.senat.fr/rap/r99-358/r99-3583.html

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.
« Last Edit: September 08, 2012, 10:00:40 pm by PaulMM »

Offline Archibald

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Re: French nuclear-powered amphibious assault ship (PH 75/PA 75)
« Reply #5 on: July 29, 2011, 08:40:34 am »
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.
Conservatoire de l'Air et de l'Espace d'Aquitaine - Bordeaux - Mérignac / Dassault aviation museum
http://www.caea.info/en/plan.php

Offline blackstar

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Re: French nuclear-powered amphibious assault ship (PH 75/PA 75)
« Reply #6 on: July 29, 2011, 11:48:16 am »
"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.
« Last Edit: September 08, 2012, 10:00:22 pm by PaulMM »

Offline Grey Havoc

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Re: French nuclear-powered amphibious assault ship (PH 75/PA 75)
« Reply #7 on: July 29, 2011, 12:27:59 pm »
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?

Offline Grey Havoc

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Re: French nuclear-powered amphibious assault ship (PH 75/PA 75)
« Reply #8 on: July 31, 2011, 04:16:51 am »
[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.
« Last Edit: September 08, 2012, 01:42:01 pm by PaulMM »

Offline GTX

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Re: French nuclear-powered amphibious assault ship (PH 75/PA 75)
« Reply #9 on: March 29, 2014, 05:07:35 pm »
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.


Offline H_K

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Re: French nuclear-powered amphibious assault ship (PH 75/PA 75)
« Reply #10 on: March 29, 2014, 08:04:01 pm »
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:
http://warships1discussionboards.yuku.com/topic/11451/RAN-OriskanyCVA01-staff-paper-costing-etc?page=3
http://warships1discussionboards.yuku.com/topic/20660/Small-1960s-Aircraft-Carrier-Question?page=3#


Offline GTX

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Re: French nuclear-powered amphibious assault ship (PH 75/PA 75)
« Reply #11 on: March 29, 2014, 10:21:35 pm »
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?