DRASS

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Drass SDVs revealed
Flag The secrecy surrounding Italian Swimmer Delivery Vehicle (SDV) manufacture is legendary. Drass are an established name in the defense industry supplying hyperbaric chambers for diver decompression. They also offer a range of SDVs and midget submarines based directly on the previous Cos.Mo.S designs. Their connection to Cos.Mo.S has been known in relevant circles but it is only very recently that they went public with their new-build SDV offering, and you still may not find any information on their website (at time of writing). This article introduces the SDV types and cross-references them to the Cos.Mo.S design heritage.

Before involvement with the Cos.Mo.S designs, Drass (formerly Roberto Galeazzi) had previously designed SDVs:
Drass SDVs - Covert Shores
From Drass website

Based in La Spezia, conveniently near to the Italian naval Special Forces (COMSUBIN), Drass were close neighbors of Cos.Mo.S during the time that the latter was a major midget submarine and SDV exporter. So it is not entirely Surprising that Drass have taken over the Cos.Mo.S designs after they went out of business (see notes HERE). Although the fundamental designs are established classics from Cos.Mo.S, Drass has incorporated up to date lithium-ion battery technology, a new control and navigation module and the latest generation of sensors.
Drass SDVs - Covert Shores

DG2 EN 2-man SDV
Drass SDVs - Covert Shores
The DG2 EN design is a direct evolution of the Cos.Mo.S CE2F X100 design and is intended purely as an offensive system to carry two combat swimmers From a host submarine (or vessel) to within range of their enemy ships in port or at anchor.

Main article: Cos.Mo.S CE2F chariot

Drass SDVs - Covert Shores
The hull is still recognizable as the CE2F but is rearranged with the crew air bottles moved inside the hull (not below the hull) and the belly payload removed. This is similar to the Cos.Mo.S CE3F design which was produced for South Korea. And like the CE3F, the canopy structure has lost its ‘head and shoulders’ cross-section. The payload is carried behind the crew in a locker on the back of the boat.

DG2 EN Specification
Length: 7.56 m
Width: 0.8 m without hydroplanes
Height: 1.3 m
Weight (dry): 2.4 tons
Crew: 2
Range: 80 nm
Speed: 4.8 kt max, 3.5 kt cruising
Operating depth: TBC
Host submarine transit depth: 100m
Payload: Special Forces stores or 6 limpet mines carried in locker on back of craft

Drass SDVs - Covert Shores


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DS4 4-man SDV
The DS4 is a minimal evolution of the Cos.Mo.S CE4F project for the Turkish Navy's SAT (Su Altı Taarruz) in the late-1990s to early-2000s.
Drass SDVs - Covert Shores

The design does not have some of the post-delivery alterations which were added to the CE4F (see below) but does have the additional stabilizers running along the lower hull.
Drass SDVs - Covert Shores

Main article: Cos.Mo.S CE4F

Drass SDVs - Covert Shores
Drass SDVs - Covert Shores

DS4 Specification
Length: 8.6 m
Width: 1.44 m hull diameter, 2.0 m max with
Height: TBC
Weight (dry): 3.49 tons
Crew: 2 + 2 PAX
Range: 110 nm
Speed: 7.5 kt max, 5 kt cruising
Operating depth: 50 m
Host submarine transit depth: 100m
Payload: Two sealed containers for Special Forces stores or limpet mines. Provision for 8 mini-torpedoes.
Drass SDVs - Covert Shores

Drass SDVs - Covert Shores
Drass SDVs - Covert Shores
Drass SDVs - Covert Shores
These photos, used by Drass in reference to the DS4, are of the Cos.Mo.S CE4F before delivery to Turkey

DS6 6-man SDV
The DS6 is Drass’ answer to the 6-man SDV market which is dominated by US, French and British designs. This allows a team of four Special Forces operators to be transported for a cross-beach mission.
Drass SDVs - Covert Shores
Analogous to the unbuilt Cos.Mo.S CE6F design, the DS6 is a lengthened DS4 with an additional row of diver’s sitting in the rear compartment. The air supply is increased but otherwise most systems remain the same, leading to a slight compromise in performance to accommodate the extra passengers.

DS6 Specification
Length: 9.1 m
Width: 1.44 m hull diameter, 2.16 m max with
Height: TBC
Weight (dry): 3.66 tons
Crew: 2 + 4 PAX
Range: 70 nm
Speed: 7 kt max, 5 kt cruising
Operating depth: 50 m
Host submarine transit depth: 100m
Payload: Two sealed containers for Special Forces stores or limpet mines. Provision for 8 mini-torpedoes.


Related articles
Flag Cos.Mo.S CE2F chariot
Flag Cos.Mo.S Nessie Fast SDV submersible boat

Flag Cos.Mo.S CE4F 4-man SDV

Flag Vogo 'Chariot' SDVs (SDV-300, SDV-340...)

Flag COMSUBIN's submersible boat

Flag Flag EMT FWS-1 to -5 Barracuda SDVs