The MKVIII MOD 1 SEAL deliver vehicle is the backbone of the last mile delivery of covert SOF forces, particularly U.S. Navy Seals. It’s effectively a fully flooded submersible that allows special operations to complete covert infiltrations, direct action raids, hydrographic recon and other infil/exfil activity without being discovered. It can also be carried to remote locations via a DDS-equipped submarine, the MK V SOC or other surface ships. In order to understand the purpose and potency of this vehicle, you have to look to its inspiration, and if you’ve read much of our stuff – you’re picking up on a theme which is we have to go back to the OSS and see what groundwork they laid.
Lambertsen realized swimmers, even using rebreathing technology, would be unnecessarily exposed and exhausted swimming miles to shore, so they envisioned the ‘Sleeping Beauty’, a submersible canoe like vehicle that would ferry swimmers closer to their objective. Here you see two OSS Maritime Unit swimmers making their way towards a target in Burma.
The ‘Gator Class’ SDV has been the crux of the special operations swimmer delivery options since the cold war, capable of inserting six to eight simmers plus their gear within range of the beach. The SDV features its own compressed air system which extends the range of the combat divers and a high-grade lithium ion battery helps power and operate the propulsion, navigation, life support equipment and comms.
For this reason, the MK8 is an excellent option for delivering SEALs to remote sites and can be set in loiter mode in an area to retrieve SEALs and return back to base. The SDVs are typically launched from the Dry Deck Shelter on the back of a submarine or other amphibious carrier which typically operate in waters no shallower than 60 feet, however this range can extend several miles around most shorelines. We should note you can also drop an SDV from a C-130 which is just awesome.
However, as the U.S. reduces its footprint in the middle east from a boots on ground perspective, the navy special warfare unit is beginning to re-assess and rebuild its maritime capabilities and will soon take delivery of the MK 11. In order to understand why the latest SDV is needed and how they are actually effective, it helps to go back to the beginning and understand the key develops between the ‘Sleeping Beauty’ and the current MK8.
Way back in 1952, the Office of Naval Research, Panel on Underwater Swimmers prepared a classified report entitled, you guessed it, “Underwater Swimmers” which described the basic task of swimmer delivery vehicles. Note the early definition actually stood for ‘Swimmer Delivery Vehicles’, but was revised to SEAL Delivery Vehicle once the UDT teams were converted to SEAL teams.
Two thirds of the earth’s surface is covered in water. Millions of people live along hundreds of thousands miles of coastline. Some say there’s no point to SDVs; I say it’s just a matter of time. SDVers are carrying on the Frogman tradition, don’t forget that.
U.S. Navy SEAL
The first production SDV utilized by the U.S Navy and probably the first operationally deployable SDV to a combat zone was the MK7, which comprised 6 different configurations. The Mod 6 version is probably the most heavily utilized and entered service in 1967 and by 1972 was being utilized by Frogmen in North Vietnam behind enemy lines. The Mod 6 could transport four divers covertly with minimal acoustic or magnetic signature owing to its fiberglass and non-ferrous material composition. All instruments were secured in water-tight compartments and the craft was easily deconstruct-able for maintenance. The MK7 also had integrated compressed air life-support and ballast systems and was propelled by an electric motor – much like the current models. This design would go on to inform the design process of the MK 7, MK8, MK9 and up through the MK11.
The MK8 SDV began replacing the MK7 in the early 80s, and at this point could carry six fully equipped combat divers or two to three divers in addition to limpet mines or the MK 36 charge. Like the MK7, the MK8 featured electrically powered rotors, Doppler Inertial Navigation System (DINS), the forward focused obstacle avoidance sonar (OAS) and the submarine rendezvous and docking system also called the RDS. Given this structure, the primary mission set became covert mine recon and demo missions, most commonly deployed during Desert Storm and OIF to secure off-shore oil platforms, although as the SEALs began picking up in-country assault duties these missions transitioned to other EOD and Engineer Dive companies.
The MK9, typically in MOD 0 format, was again taking the SEALs back to hydrographic recon and larger weapons delivery, featuring a low-profile design most efficient for ship attached and other harbor-based sabotage. This SDV was actually piloted in the prone position and was better situated for shallow water insertion and operations. It also featured the DINS, OAS and RDS systems, however it also featured the SWA or stand-off weapon system was essentially a classified modification of the MK37 submarine torpedo.
This leads us to the MK11, note there was no materially deployed MK10 owing to the almost full commitment of SEALs to ground combat operations in Iraq, Afghanistan, Horn of Africa and the Philippines. Naval Special Warfare (NSW) is in the process of taking delivery now of the MK11, a slightly larger version of the MK8 at 22 feet and nearly 4000 lbs. more. This will allow further capabilities for covert maritime assault and sabotage. The current contract is with Teledyne Brown and will see the firm deliver 10 fully functional MK11 SDVs – ushering in a new period of special operations diving.
