Sphyrene SDV

Thank you to an unnamed source. Any errors are entirely my responsibility
Flag Flag Sphyrene + Coryphene SDVs
The Sphyrene is an advanced six-man Swimmer Delivery Vehicle (SDV) currently on the market from French firm Alseamar. It is one of the latest generation of French SDVs tracing its lineage back to the Vostock SDV used by Commando Hubert. The Sphyrene is promoted on the export market alongside French diesel-electric submarines and Alseamar's updated Vostock, the Coryphene.

Some French SDV History
The French contribution to post-war special forces technology is often under-appreciated beyond their borders. Largely invisible to the outside world, within the community of Western Naval Special Forces (SEALs, SBS…) Commando Hubert has forged particularly strong links and had a two-way exchange of ideas and tactics. This history is broadly relevant to both American and British Special Forces buffs. Here we will deal mainly with the personalities and underwater vehicles.

The pioneers included the Famous Jacques Cousteau who played a part in the development and promotion of air SCUBA gear (invented after the rebreather!) and then of underwater vehicles in the 1950s. He enjoyed a degree of international fame and is remembered for lots of diving related things but perhaps less well known is that his organisation, GERS, developed the military application of one-man diver propulsion devices which he termed Tracteurs. Less famous that Cousteau was Dimitri Rebikoff who was a contemporary who developed his own line of underwater scooters which are generally known as the Pegasus family. Rebikoff’s designs had a much greater influence on the SEALs and SBS than Cousteau’s. an under-recognized hero.
Coming years after Cousteau and Rebikoff, Jean C Havas developed a long line of SDVs from the late 1960s. Switching to the secretive military market soon after starting Havas never enjoyed the limelight of the other two.
Left: Cousteau's tracteurs being demonstrated in a civilian setting. Middle: Rebikoff's Pegasus. This one is in the UDT/SEAL Museum. Right: An early Havas craft, again in a civilian setting.

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When it came to equipping the Commando Hubert's Nageurs de Combat GER was an official government organization and so had an advantage. The first underwater vehicles used by Commando Hubert were the TSM (Tracteur Sous-Marins) which was a GER trateur with basic navigation aids and a large detachable anti-ship mine carried on the nose.
TSMs in use. The difficulty of keeping formation and navigating in the dark can easily be imagined

Mind your French!

The limitations of single-diver vehicles were self-evident and the follow-on design was to be a two-man craft in the chariot style. The PSM (Propulsor-Sous-marins)Vostock was a uniquely French design broadly equivalent to the Italian made Cos.Mo.S CE2F Chariots. The hull was a streamlined fibreglass construction with the two crew sitting in a cockpit near the front. In a hint to the future there was a transparent perspex water-shield and canopy but it provided limited visibility forwards. Diving at night or in murky waters there wasn't much to see out the front anyway.

One of the limitations of operating the Vostock was that French Navy submarines were not equipped to carry them. This was at a time when only the USN and Italians (very secretive!) among major navies had an operational way of attaching SDVs. Mid-tier navies tended to simply lash them onto the outside but this had serious limitations. So the French invented a detachable hangar which can be flooded or drained whilst the submarine is submerged, allowing it to operate underwater. The French called this a valise meaning 'suitcase', but we know it today as a Dry Deck Shelter (DDS). The French were about ten years ahead of the USN in this regard. The early shelters were significantly smaller and less sophisticated than their USN equivalents but that's part of being first.
Early prototype DDS, mid-1970s
Agosta Class SSKwith DDS and representative SDV highlighted behind the 'kiosk' (sail). Note that the divers have to exit from the main lock-out chamber forward (also highlighted) and swim aft to access the DDS

The Vostock and TSM served alongside each other for many years. In the meantime SDV technology was advancing and the craft were getting old. The Vostock-NG was a rebuild of some of the earlier Vostocks.
Eventually the Vostock-NGs got old too and the Agosta class SSKsused to transport them were retired, and the capability was wound down. The current diver transport in use by Commando Hubert is the US made Stidd-DPD although French Special forces units use several other diver propulsion devices.

Coryphene SDV
The Coryphene is a thoroughly updated Vostock with completely new internal systems bringing it right up to date. New sensors (sonar, optronics), navigation and propulsion is fitted.

Coryphene Specifications
Length: 6m for two man version, 6.3m for three man version
Beam: 1m
Height: 1m
Weight: 1.5 tons
Speed: 8kts max
Endurance: 80 nautical miles @ 5 kt
Operating depth: 25m
Maximum depth: 100m
Stopping distance: 100m
Turning radius: 60m
Personnel: 2 crew plus up to 1 passenger (with hull extension)
Optional: Telescopic mast with optronics system

Sphyrene SDV
The Sphyrene has a six-man 'wet' cockpit in the front of he craft which is flooded when the craft is submerged. Above this is a folding mast about 3m long, and behind it is the aft section which is fully sealed and contains a spacious battery compartment and electric motor. The control arrangement is thoroughly modern with two sets of both vertical and horizontal thrusters and an 'X' plan tail. It is available in a number of configurations including both 'fly by wire' and cable controls, smaller cockpits and '+' plan tail.

The lower image shows the Sphyrene in a 'wet deck shelter' carried on the side or top of a mother submarine. Although not as versatile as a dry deck shelter (DDS, 'Suitcase' in French parlance) this allows the mother submarine to travel faster than if it was carried externally.

Sphyrene Specifications
Length: 8m
Beam: 1.4m
Height: 1.4m
Displacement: 4 tons
Speed: 9kts
Endurance: 120 nautical miles
Operating depth: 25m
Maximum depth: 100m
Stopping distance: 100m
Turning radius: 60m
Personnel: 2 crew plus up to 4 passengers

1. Large diameter screw-back propeller
2. 'X' configuration all-moving tail surfaces
3. Electric motor
4. Aft vertical thruster
5. Aft horizontal thruster
6. Aft trim tank
7. Battery
8. sliding canopy
9. mast casing
10. Electro-optical mast
11. Onboard air supply
12. Instrument panel
13. Forward vertical thruster
14. Forward trim tank
15. Forward horizontal thruster
16. Obstacle avoidance sonar


Submarine builder DCNS have unveiled their SMX-Ocean export submarine which is essentially a diesel-electric version of the nuclear-powered Barracuda design. The marketing emphasises its versatility which includes a DDS. The SDV shown differs from the other two designs described but is broadly equivalent. Again, note the holes at the side and top of the nose for thrusters.


Many thanks to everyone who have made this possible More info

Sub-Sea Light Vehicle (SLV)
An Alseamar designed Diver Propulsion Device. possibly also called MURENE. Info pending.

USSV (Unmanned Sub-surface Vehicle)
USSV Specifications
Lenght: 1.80 m
Width: 0.70 m
Height: 0.60m
Weight: <100 Kg in air
Speed: Up to 3 Kts

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