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DRASS
Mon 13 November 2017By H I Sutton
Updated. Originally posted 10th June 2017.
This article relies heavily on information from unnamed individuals. Sincere thanks to everybody who has helped.Information and corrections welcome. Contact the author HERE
Drass SDVs and midget submarines
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:
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.
Get The essential guide to World Submarines
This Covert Shores Recognition Guide Covers over 80 classes of submarines including all types currently in service with World Navies.
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DG-160 Shallow-water Attack Submarine
The largest DRASS midget-submarine, the 140 ton DG-160 is reminiscent of the unbuilt Cos.Mo.S X-201 SWATS submarine concept but with a more conventional ‘+’ tail section based on the MG-120 design.
left: photo of Cos.Mo.S MG-120 bow with twin torpedo tubes and sonar dome on top, right: CG of DG-160 with two DRASS DG2 SDVs on deck.
CLICK for HIGH-RESOLUTION image.
![](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2FDRASS_DG160_cutaway940.jpg&hash=a1eef857752e4521457be782d6e31920)
DG-160 Specification
Displacememt: 141 tons surfaced, 169 tons submerged
Length: 32.24 m
Width: 2.5 m hull diameter, 4.12 m with hydroplanes
Height: 6.45 m
Crew: 7 + 8 PAX
Range: 2,000 nm, 160 nm on batteries
Speed: 10 kt max, 5 kt cruising, 8.5 kt surfaced
Operating depth: TBC
Armament: 2 x 533mm torpedoes standard, plus 2 x 533mm torpedoes or 6 x mines in laterial tubes as mission-specific load
Other: 2 x SDVs or up to 6 x inflatable boats
Equipment: Passive sonar, active sonar, SWR Intercept Sonar, Radar Warning Receiver, TV periscope, Underwater Communications, Ring-Laster gyrocompass, echosounder, doppler velocity log, Electromagnetic log
DG-120 Shallow-water Attack Submarine
The DG-120 sacrifices Special Forces payload for a larger complement of wire-guided 400mm torpedoes with 11 nautical miles range. Only two commandos can be carried in addition to the seven-person crew.
DG-120 Specification
Displacememt: 115 tons surfaced, 130 tons submerged
Length: 28.2 m
Width: 2.3 m hull diameter, 3.92 m with hydroplanes
Height: 6.4 m
Crew: 7 + 2 PAX
Range: 1,800 nm, 120 nm on batteries
Speed: 9 kt max, 4 kt cruising, 7.5 kt surfaced
Operating depth: TBC
Armament: 6 x 400mm torpedoes, 6 mines.
Other: 1 x inflatable boat
Equipment: Passive sonar, active sonar, SWR Intercept Sonar, Radar Warning Receiver, TV periscope, Underwater Communications, Ring-Laster gyrocompass, echosounder, doppler velocity log
DG-85 Shallow-water Attack Submarine
The smallest of the DRASS midget submarine designs, the DG-85 is intended for a) attacks on ships moored in harbor or harbor installation using the 6 mines which are carried externally, b) patrol of coastal areas as deterrent against enemy ships approaching own coastal targets using 400mm wire-guided torpedoes, c) Intelligence gathering using acoustic, electronic and communication (SIGNIT) sensors, and d) deployment of mines in very shallow waters / harbor mouths.
Mon 13 November 2017By H I Sutton
Updated. Originally posted 10th June 2017.
![](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2Ftwitter.jpg&hash=ede181e5c6b7a56774fc354b0b07800d)
Drass SDVs and midget submarines
![](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2FDrass_logo.jpg&hash=46a108063868a87acc9b52d453554748)
![flag_italy.jpg](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2Fflag_italy.jpg&hash=3d65efb716dbf81d9beba6e160cce52a)
Before involvement with the Cos.Mo.S designs, Drass (formerly Roberto Galeazzi) had previously designed SDVs:
![Drass_SDV.png](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2FDrass_SDV.png&hash=e1bb40310d3cc5e55990b88c1c4175ce)
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_CE4F_2.jpg](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2FDrass_CE4F_2.jpg&hash=7f0372363f26095df67e3ea9f8a26664)
![DRASS_series.jpg](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2FDRASS_series.jpg&hash=7c1c9e87a7dd4c4f6e1d563ac701ef00)
![](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2FBook_WorldSubsCover175.jpg&hash=6b1498d2539b7d306455dd9c5883e100)
Get The essential guide to World Submarines
This Covert Shores Recognition Guide Covers over 80 classes of submarines including all types currently in service with World Navies.
![](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2FBook_Walrus400.png&hash=bcf435355fd0228241b0347127b2952a)
DG-160 Shallow-water Attack Submarine
![DRASS_DG160_schematic1.jpg](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2FDRASS_DG160_schematic1.jpg&hash=979caaba49c1898eb2c3b5efadba717b)
The largest DRASS midget-submarine, the 140 ton DG-160 is reminiscent of the unbuilt Cos.Mo.S X-201 SWATS submarine concept but with a more conventional ‘+’ tail section based on the MG-120 design.
![DRASS_DG160_bow.jpg](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2FDRASS_DG160_bow.jpg&hash=8f3cc435bed362fda7fa82099f32aa63)
left: photo of Cos.Mo.S MG-120 bow with twin torpedo tubes and sonar dome on top, right: CG of DG-160 with two DRASS DG2 SDVs on deck.
CLICK for HIGH-RESOLUTION image.
![](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2FDRASS_DG160_cutaway940.jpg&hash=a1eef857752e4521457be782d6e31920)
DG-160 Specification
Displacememt: 141 tons surfaced, 169 tons submerged
Length: 32.24 m
Width: 2.5 m hull diameter, 4.12 m with hydroplanes
Height: 6.45 m
Crew: 7 + 8 PAX
Range: 2,000 nm, 160 nm on batteries
Speed: 10 kt max, 5 kt cruising, 8.5 kt surfaced
Operating depth: TBC
Armament: 2 x 533mm torpedoes standard, plus 2 x 533mm torpedoes or 6 x mines in laterial tubes as mission-specific load
Other: 2 x SDVs or up to 6 x inflatable boats
Equipment: Passive sonar, active sonar, SWR Intercept Sonar, Radar Warning Receiver, TV periscope, Underwater Communications, Ring-Laster gyrocompass, echosounder, doppler velocity log, Electromagnetic log
![DRASS_DG160_schematic.jpg](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2FDRASS_DG160_schematic.jpg&hash=43ac959b9dc42eb80299e1add8668309)
![DRASS_DG120_water.jpg](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2FDRASS_DG120_water.jpg&hash=21c01f2495fccde3e539f31977490b06)
DG-120 Shallow-water Attack Submarine
The DG-120 sacrifices Special Forces payload for a larger complement of wire-guided 400mm torpedoes with 11 nautical miles range. Only two commandos can be carried in addition to the seven-person crew.
![DRASS_DG120a.jpg](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2FDRASS_DG120a.jpg&hash=0ac59b19de97b6f3ec71814062d5cce4)
![DRASS_DG120b.jpg](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2FDRASS_DG120b.jpg&hash=28151e39993d6bda7072a328943f308f)
![DRASS_DG120_inside.jpg](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2FDRASS_DG120_inside.jpg&hash=2814aa8737c5209883803d84f8375ae0)
DG-120 Specification
Displacememt: 115 tons surfaced, 130 tons submerged
Length: 28.2 m
Width: 2.3 m hull diameter, 3.92 m with hydroplanes
Height: 6.4 m
Crew: 7 + 2 PAX
Range: 1,800 nm, 120 nm on batteries
Speed: 9 kt max, 4 kt cruising, 7.5 kt surfaced
Operating depth: TBC
Armament: 6 x 400mm torpedoes, 6 mines.
Other: 1 x inflatable boat
Equipment: Passive sonar, active sonar, SWR Intercept Sonar, Radar Warning Receiver, TV periscope, Underwater Communications, Ring-Laster gyrocompass, echosounder, doppler velocity log
![DRASS_DG120_schematic.jpg](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2FDRASS_DG120_schematic.jpg&hash=8eb802e2c204810e1f8a087ea72ddec9)
DG-85 Shallow-water Attack Submarine
The smallest of the DRASS midget submarine designs, the DG-85 is intended for a) attacks on ships moored in harbor or harbor installation using the 6 mines which are carried externally, b) patrol of coastal areas as deterrent against enemy ships approaching own coastal targets using 400mm wire-guided torpedoes, c) Intelligence gathering using acoustic, electronic and communication (SIGNIT) sensors, and d) deployment of mines in very shallow waters / harbor mouths.
![DRASS_DG85a.jpg](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2FDRASS_DG85a.jpg&hash=00335e844ce2e81f1c7b9839c72bc718)
![DRASS_DG85.jpg](/proxy.php?image=http%3A%2F%2Fwww.hisutton.com%2Fimages%2FDRASS_DG85.jpg&hash=8614fe61e1016868f401206852a6305c)