French Nuclear Submarines

[uk 75]

The close relationship between the USN and RN in operating their submarine forces is well documented.
But little is available in the UK about the operations of the French submarine fleet in and after the Cold War.
The small number of Rubis class SSNs commissioned from the 70s seem to be have intended to protect the SSBNs.
I have put this in the Alternate History section because I suspect that despite the fractious politics between France and the UK/US there are both real and fictional stories to be told.

 

[H_K]

The small number of Rubis class SSNs commissioned from the 70s seem to be have intended to protect the SSBNs.

One important factoid is that the French SSNs are the only SSNs in the world which are double crewed: there are 10 Red/Blue crews for 5 operational subs (with a 6th sub always in refit).

AFAIK, in the RN and USN only SSBNs have such a crewing arrangement.

As a result the French SSNs spend a lot of time at sea… Saphir retired after 36 years having dived 5,000 days! That’s 140 days per year, despite time spent in refit & refueling. Typically the 5 operational subs spend 800-900 days at sea each year (160-180 days each). The record not that long ago (2016) was 1,000 days at sea… 200 days per operational boat, which is quite impressive given an average fleet age of 30+ years.

There’s a lot of uninformed commentary about how the frequent refuelings (every 7-8 years) and use of low enriched uranium is a weakness, but based on the above statistics the French get a ton of mileage from their SSNs.

This allows them to have 2 SSNs deployed most of the time despite a small fleet - one SSN in the Atlantic and one in the Med/Indian Ocean, with a 3rd sub working up. Sub #4 would be pierside, sub #5 in short-term maintenance, and sub #6 in long refit/refueling.

 

[H_K]

To add some comparisons:

1) HMS Torbay (Trafalgar class): 2,415 days dived, 705,000 miles steamed in 32 years service (1985-2017)
vs. MN Saphir (Rubis class): >5,000 days dived, 1,200,000 miles steamed in 36 years service (1983-2019)

2) The RAN proudly trumpeted that their 6 Collins SSKs achieved a record 600 days at sea in 2018, surpassing “international benchmarks” (!) ... yet this is much less than the 800-900 days at sea the 6 Rubis SSNs have been doing for decades. And the RAN has the benefit of fairly new subs and none of an SSN’s complex maintenance or refueling needs.

Can’t help but think that the RN and RAN subs’ operational tempo would be considered woeful in the Marine Nationale…

 

[uk 75]

Thank you H_K. We need much more here about the Marine Nationale. The RN and USN get a lot of focus already.
I assume the Atlantic SSN helps the SSBN come and go safely as well as other duties like shadowing transiting warships.
The MN has been traditionally very active in the Mediterranean. There is a lot of trade there.
The Indian Ocean has seen regular carrier deployments over the years. I assume an SSN is always around these.
Given the dashing traditions of the French military I imagine all 6 SSNs have some pretty interesting missions under their belts.
To meet the alternate history here it would be interesting to know what paths might have been taken by France.
The trials sub Gymnote used for developing SLBM was supposed to be the first SSN.
Did the US offer Skipjacks as it did to Italy and Canada?

 

[Hood]

Did the US offer Skipjacks as it did to Italy and Canada?

Friedman supposes so but he hasn't found archival evidence to back that up.
Given they offered the tech to Italy and the Netherlands - both rather small naval powers with tiny submarine forces and no great pressing need for nuclear subs - it would be very surprising that there wasn't an offer to France.
After all France's needs were similar to the UK's.

I suspect the offer was declined in order to protect France's own nuclear industry, they have never been big users of foreign warships or naval armaments either. In fact I'm struggling to think of many, if any, US/NATO naval systems France used beyond those it developed in cooperation with its own industries.

 

[Archibald]

I can confirm Skipjacks were offered in 1962. It was a trick by the two Europeanists Deans (Archeson and Rusk, not Dean Martin ) to try and buy France out of the nascent - and damn expensive - Force de Frappe; and provide NATO MLF instead: Polaris on surface ships.

The Deans felt that independant European nuclear deterrents (GB and France together) were not only immense waste of money, they were also dangerous.

De Gaulle told them politely "no". The Deans also tried to do the same to the British at Nassau (if you want Polaris, you will get them via the MLF - otherwise forget it) but MacMillan managed to negociate an "escape clause" giving GB control over them in case of a major, national crisis.

See attached document.

 

[Archibald]

France tried to build first a submarine using heavy water; the hull was called Q244 but it was found to be unworkable.
This partially completed hull was turned into the Gymnote non-nuclear submarine (the irony !) that spent the next three decades firing all French prototype SLBM from M1 to M4 in the mid-80's.

French submarine Gymnote (S655) - Wikipedia

en.wikipedia.org

I was surprised to learn the British started with SSNs (Dreadnought / Valiants) and then moved to boomers.

The french started the opposite way: boomers first (Redoutable, Q252 hull) and after a decade in the 80's, the Rubis SSN presently retiring - the smallest SSN in the world.

Redoutable-class submarine (1967) - Wikipedia

en.wikipedia.org

 

[uk 75]

The Rubis class must have certain advantages for clandestine ops with their small size.
Have any stories real or imagined come out The horn of Africa comes to.mind.

 

[Hood]

I was surprised to learn the British started with SSNs (Dreadnought / Valiants) and then moved to boomers.

As Macmillan would say "events dear boy", an artefact of timing in 1956 the idea of a ballistic missile submarine still seemed like sci-fi when stuff like Regulus looked like a Heath Robinson contraption.
Actually the SSBN was seen as a nuisance in disrupting the SSN programme, probably another four or five Valiants would have been built instead. The RN wasn't necessarily super keen on getting the national deterrent, they knew they could probably get the SSN dosh out of the Treasury.

Actually it was probably wise to practice silencing and find out what worked in terms of rafting and insulation before building the Resolutions which really did rely on silence.

 

[orlovsky]

I haven't seen a thread for the Rubis class per se, so two sources on the Rubis development:

1983 : La France se dote de sous-marins nucléaires d'attaque | Mer et Marine

A la fin des années 70, la flotte stratégique française prend corps. En septembre 1977, un cinquième sous-marin nucléaire lanceur d'engins, le Tonnant, est

www.meretmarine.com

Naissance du SNA : du sous-marin hautes performances au SNA 72 (1964 - 1976)

Blog proposant souvent de suivre les programmes anciens, nouveaux de la Marine nationale et parfois de faire de même pour les marines étrangères.

lefauteuildecolbert.blogspot.com

The goal changed from an SNC (hunter) to an SNA (attack). One version of the SNA 69 would have had 18 MW for 4000 tons (688 class: initially 22 MW for 6000 tons), so this would have been interesting.

The resulting SNA 72 (Rubis) was a nuclear Agosta and according to other french documents limited in the ASW role. Not entirely clear why: small size, turboelectric drive, 20 kts with natural circulation, 25 kts max speed - essentially a much improved USS Tullibee (The US Navy never got happy with the dreict drive) . Maybe the lack of the Albacore shape, as the sonar got disturbed at higher speeds. Seems to habe been remedied with the Améthyste design and refits. Quite interesting from the mer et marine article:

"Les Agosta ne sont pas des navires très rapides. En raison de leur propulsion diésel, ils ne peuvent rester longtemps à 20 noeuds et opèrent la plupart du temps à 4, 6 ou 8 noeuds. ... Quand on entend bien à 8 noeuds, ce n'est pas forcément le cas à 20. Si la forme de l'avant n'est pas profilée, elle provoque des bruits. Il ne faut pas que le sonar soit perturbé par son propre porteur car, à partir d'une certaine vitesse, on entend beaucoup moins bien."

Given the US and UK experience, it's odd that they inituially used the Agosta shape in the design.

The Rubis have less space for supplies and crew comfort, the normal mission time is given as 45-60 days. The double-crewing probably makes more sense than for the larger SSNs with much longer missions.

For the "noisy" verdict, there's a whole passage in the mer et marine article:

"Concernant le niveau de discrétion des Rubis, Xavier Itard tient à relativiser les critiques, parfois radicales : Il est vrai que c'était une génération où, en matière de discrétion acoustique, on a fait ce que permettait la technologie de l'époque. Avec le Triomphant, nous avons fait un énorme saut, mais, sur les Rubis, les équipements étaient déjà suspendus."

I'm not sure whether this means rafting as in the RN SSN/SSBN?

Also seems there was continious work on the screw design:

"Un gros travail a, notamment, été réalisé sur les hélices, grâce aux équipements du Bassin d'Essais des Carènes de Val de Rueil (***). Les Rubis disposent aujourd'hui de pales retravaillées et profilées de manière à réduire les indiscrétions."

The version proposed for Canada would have been a stretched Améthyste with 22 instead of 14 torpedoes.

Missions:
- probably not very glorious, Rubis was supposedly involved in the operation of the rainbow warrior sinking
- The SSNs blocked the Kotor base in the Kosovo war
- Libya war: only standby (at least officially)

 

[Archibald]

rafting

Yes. "suspendu" literally means "hanged".

 

[TinWing]

I haven't seen a thread for the Rubis class per se, so two sources on the Rubis development:

1983 : La France se dote de sous-marins nucléaires d'attaque | Mer et Marine

A la fin des années 70, la flotte stratégique française prend corps. En septembre 1977, un cinquième sous-marin nucléaire lanceur d'engins, le Tonnant, est

www.meretmarine.com

Naissance du SNA : du sous-marin hautes performances au SNA 72 (1964 - 1976)

Blog proposant souvent de suivre les programmes anciens, nouveaux de la Marine nationale et parfois de faire de même pour les marines étrangères.

lefauteuildecolbert.blogspot.com

The goal changed from an SNC (hunter) to an SNA (attack). One version of the SNA 69 would have had 18 MW for 4000 tons (688 class: initially 22 MW for 6000 tons), so this would have been interesting.

The resulting SNA 72 (Rubis) was a nuclear Agosta and according to other french documents limited in the ASW role. Not entirely clear why: small size, turboelectric drive, 20 kts with natural circulation, 25 kts max speed - essentially a much improved USS Tullibee (The US Navy never got happy with the dreict drive) . Maybe the lack of the Albacore shape, as the sonar got disturbed at higher speeds. Seems to habe been remedied with the Améthyste design and refits. Quite interesting from the mer et marine article:

"Les Agosta ne sont pas des navires très rapides. En raison de leur propulsion diésel, ils ne peuvent rester longtemps à 20 noeuds et opèrent la plupart du temps à 4, 6 ou 8 noeuds. ... Quand on entend bien à 8 noeuds, ce n'est pas forcément le cas à 20. Si la forme de l'avant n'est pas profilée, elle provoque des bruits. Il ne faut pas que le sonar soit perturbé par son propre porteur car, à partir d'une certaine vitesse, on entend beaucoup moins bien."

Given the US and UK experience, it's odd that they inituially used the Agosta shape in the design.

The Rubis have less space for supplies and crew comfort, the normal mission time is given as 45-60 days. The double-crewing probably makes more sense than for the larger SSNs with much longer missions.

For the "noisy" verdict, there's a whole passage in the mer et marine article:

"Concernant le niveau de discrétion des Rubis, Xavier Itard tient à relativiser les critiques, parfois radicales : Il est vrai que c'était une génération où, en matière de discrétion acoustique, on a fait ce que permettait la technologie de l'époque. Avec le Triomphant, nous avons fait un énorme saut, mais, sur les Rubis, les équipements étaient déjà suspendus."

I'm not sure whether this means rafting as in the RN SSN/SSBN?

Also seems there was continious work on the screw design:

"Un gros travail a, notamment, été réalisé sur les hélices, grâce aux équipements du Bassin d'Essais des Carènes de Val de Rueil (***). Les Rubis disposent aujourd'hui de pales retravaillées et profilées de manière à réduire les indiscrétions."

The version proposed for Canada would have been a stretched Améthyste with 22 instead of 14 torpedoes.

Missions:
- probably not very glorious, Rubis was supposedly involved in the operation of the rainbow warrior sinking
- The SSNs blocked the Kotor base in the Kosovo war
- Libya war: only standby (at least officially)

Rumors of a Rubis class submarine rescuing French personnel from the Rainbow Warrior incident are unfounded and based on bad journalism at the Sunday Times. As I recollect, the theory was predicated on a misunderstanding of thermal vs actual electrical output. The British author claimed the Rubis class made 48MW of power at the screw, allowing the same sort of speed as the Soviet Alfa class! For the timeline to have worked, the French sub would have had to have made nearly 40 knots! As we all know, the Rubis class actually has 7MW of propulsive power and optimistically can make 25 knots.

I've never seen a single inboard profile drawing of the Rubis class and it remains the most mysterious SSN class outside of China. From what I've seen and read, the Rubis is single hulled while the Agosta is definitely double hulled, so the SNA 72 was hardly just a nuclear powered Agosta. The outward aesthetics were very much in common until the AMETHYST rebuilding. The source for the SNC68 to SNA72 chronology appear to be "The encyclopedia of French submarines - Volume IV: The end of the Cold War , Paris, SPE Barthélémy, 2017." The book purports to be illustrated and I'd love to know if there are actual drawings of the unbuilt proposals?

In contrast, the Agosta class is pretty much an open book.