August 18, 2014

Navy SEAL and Submarine Capabilities

SEALs with rather thermal looking gear.
No submarine (from SSKs, SSNs to SSGNs) would be complete without the ability to carry a SEAL Team. US SEAL Teamscommonly known as the Navy SEALs, are the US Navy's principal special operations force and a part of the Naval Special Warfare Command and United States Special Operations Command. "SEAL" is only the US term while there are other foreign terms. Submarines can carry various SEAL dry decks shelters and vehicles of various sizes and missions. 

The SEAL acronym stands for Sea, Air, and Land, which identifies the elements in which they operate. SEALs work in small units -- often one to two men, but sometimes in a platoon comprised of up to 16. Two 8 man SEAL delivery vehicles (SDVs) could therefore carry one platoon. They are trained to perform specific tasks under any type of circumstance and in any environment. 
Missions fall into five main categories:
·    Unconventional Warfare (UW) - Using guerilla warfare tactics in battle. 
·    Foreign Internal Defense (FID) - Training given to foreign nationals in order to build relationships..
·    Direct Action (DA) - Moving against an enemy target. This may include assaults on land- or water-based targets, hostage rescues, ambushes, etc.
·    Counterterrorism (CT) - Includes direct action against terrorist operations, counter-terrorist actions for preventing terrorist acts, and protecting citizens and troops.
·    Special Reconnaissance (SR) - Includes conducting preliminary surveys to gather information, manning observation posts, and other types of surveillance, both overt and covert, where the goal is to gather information. This may include gathering hydrographic data (beach and water surveys) for landings or following an enemy unit and reporting its position.
The above categories overlap when it comes to actual missions, but these are the basis of SEAL training: to be expert in the skills required to perform these various tasks.

The object on the USS Dallas SSN submarine's back, known as the dry deck shelter, can deploy and recover free swimming SEAL divers and SEAL delivery vehicles (SDV) like the one pictured, while remaining submerged.

An SDV being maneuvered into one of the two dry deck shelters on the submarine's back.

Model of the inside of an SDV indicating it can carry as many as 8 SEALs. reported on August 1, 2014

Climb Into the Mini-Sub Navy SEALs Use to Bring Death From Below

Here’s the scenario: After suiting up with diving knives and silenced assault rifles, a team of three Navy SEALs on a submarine prepare to head to shore for a sneak attack. They put on their scuba gear and climb into a [SEAL Delivery Vehicle (SDV) that is shaped like a fat torpedo and]  not much bigger than a shower. Powered by a single rear propeller, it deploys from the [dry decks shelters of the] host submarine. After hours of slow, calculated movement through water too shallow for any submarine, radar indicates the SEALs have reached shore. Still underwater, they slide back the top canopy of their vessel and swim the last stretch to the beach under cover of night.

The key tool here is the SEAL Delivery Vehicle (SDV), the modern version of what’s essentially a tube with a propeller stuck on the back. It can be as compact as needed, sized to fit just one Navy SEAL or as many as [eight]. These craft are typically “free-flooding” vessels, which means they’re filled with water [which avoids most of the problems of buoyancy and center of gravity maintenance]. The soldiers inside breathe through their own scuba tanks or from on-board oxygen reservoirs...

The idea of a scaled-down, maneuverable submarine has been around for decades. Full-sized subs can’t operate properly in water shallower than 50 feet, so getting covert forces from ship to shore is tricky. Going in with scuba gear may require more oxygen than can be contained in a normal tank, and swimming in flippers for that long can leave even a hardened SEAL too exhausted to perform the mission.

Back in World War II, the British [Royal Navy (RN) Special Boat Service (SBS)] made a vehicle called the “submersible canoe,” or “sleeping beauty.” Soldiers trained with it and ran test missions, but it never saw live combat.

[Italy boasts the world's most successful record for SEAL/diver delivery vehicle operations. In World War Two Italy's Decima Flottiglia MAS (10th Assault Vehicle Flotilla") used manned torpedoes (known as SLC "maiales" "pigs") to destroy 72,190 tons of Allied warships and 130,572 tons of Allied merchant ships. Italians from the flotilla sank 2 Royal Navy battleships HMS Valiant, and HMS Queen Elizabeth (both of which, after months of work, were refloated and returned to action), wrecked the heavy cruiser HMS York and the destroyer HMS Eridge, damaged the destroyer HMS Jervis and sank or damaged 20 merchant ships including supply ships and tankers. Truly amazing!]

 In the early 1970s, US small craft were used off the coast of North Vietnam for combat and reconnaissance. One, the Mark VII, was built with a fiberglass hull and components made with non-ferrous metals, to minimize the craft’s radar signature. Power to the rear propeller came from two rechargeable silver-zinc batteries.

As the vessels now used by SEALs evolved, updates included Doppler navigation systems, sonar, and docking systems that reunited the unit with its host submarine once its occupants have filed out. A dry dock shelter lets soldiers move from the sub to the water, then get into the vessel.

The modern version of these “underwater swimmers” was officially commissioned in 1983 by the Naval Special Warfare SEAL Delivery Vehicle Teams. The then-new Mark VIII, which succeeded the Mark VII in the early 1980s, was designed to be much larger than its predecessors so it could move more cargo and more personnel, propelled by rechargeable batteries. The Mark VIII and its successors saw combat in Operation Desert Storm, and were used to secure offshore oil terminals during the most recent Iraq war.
 Above is a human "Torpedo SEAL" developed in the 1980s which is very similar to the highly successful WWII Italian "maiale" "pigs" human torpedoes. The Torpedo SEAL, is made by James Fisher Defence. The vessel, which is not currently used by the US Navy, can be deployed from a NATO-standard 533mm torpedo tube, or air-dropped from a helicopter. Propulsion comes from a lithium polymer battery that gets it to a top speed of 4 knots, or just under 5 mph. 

JF Defence says its “deliveries [are] often named as non-disclosed,” but that their six-man SEAL Carrier (above) "has been delivered to Sweden’s Navy" [according to]. The SEAL Carrier operates in three modes; surface, semi-submerged and submerged. Launched from a surface ship, SEAL Carrier vehicles can transit at speeds of up to 30kts on the surface before switching to submerged mode for a covert final approach.

The most recent variation on the SDV is the new the Shallow Water Combat Submersible (SWCS). Alabama-based Teledyne Brown Engineering won the $383 million contract in 2011 to design and build this new craft. We called them up, but Teledyne “respectfully decline[d] the opportunity to be interviewed.” They must be doing something cool." ENDS



larsing said...

Thanks for an informative post.However I do not agree that all submarines should have the capability to carry SEAL teams.Only for countries with a small submarine fleet is this essential.

Anonymous said...

Dear Pete,

the reason why the US does need such additional small submarines for SEAL teams is quite easily explained: the big US nuclear submarines have to avoid the coastal waters.

Like the nice pictures of the Swedish A26 with a big diver lock in front most diesel powered submarines can get closer to the shore.

German submarines can operate submerged in just 20 m of water.

The US solution to fix some shelters on a submarine can be used on any other submarine type as well.

In case something went wrong a diesel submarine in foreign waters is less embarrassing than a nuclear one.



Pete said...

Hi larsing

Thanks for your comment. Yes its true that a nation's submarines, even of the same class, would have varying SEAL delivery capabilities. Some subs might carry no dry deck shelters while others one or two shelters.



Pete said...

Hi MHalblaub

Thanks for and also .

I'm curious the extent the 218SG's might utilise some of the features of the Dolphin IIs. Singapore has close relations with Israel in some military functions.

One 218 feature may be the multi-coloured hull and sale, given the 218s will also need to operate in fairly shallow waters.

Another feature may be 2 to 4 26-inch horizontal tubes initially for launching small commando teams and perhaps large cruise missiles in years to come. Although the US may be willing to supply Tomahawks to Singapore someday which only need 21 inch horizontal tubes.

On SSK vs SSN merits Australia initially selecting 210s, 214s or 218AUs is possible. An option to also select a small number of Virginia SSNs in further decades would also be handy.