Cold War Sturgeon Class Nuclear-Powered Attack Submarine (SSN)
The main US Navy attack submarine of the Cold War, 39 Sturgeon Class SSNs were built in the late 1960s and 1970s. Their primary purpose was anti-submarine warfare against all types of seagoing Soviet submarines... 
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Seliger
Russian Seliger Deep Sea 'Research' Complex
The Soviet deep-sea research into cable cutting from submarines goes back to the mid-1960s. The Russian Seliger vehicle was used for deep sea research and 'undersea engineering' during the Cold War..... 
Russian_Arctic_Seabed_Capabilities
Large illustration of Russian Under-ice Seabed Capabilities Russia continues to take steps towards militarizing the arctic, and in particular the sea floor under the ice cap.... 
PR-77+R-2_SDVs
Classic two-man SDV of the Cold War
This one of the most widely recognized Swimmer Delivery Vehicles (SDVs) of the Cold War, and is best known as the Ronilica R-2, preferred mount of Yugoslavia’s commando frogmen unit the 82 Maritime Center. The original design is in fact French, and it served with the US Navy UDT and SEALs as well as being exported, from Yugoslavia, to Sweden, Syria and Libya..... 
NarcoSub_03-2018
Narco Sub developments and trends
This article documents recent intercepts and highlights how Narco Sub design and Modus Operandi is evolving....
OSINT_Landscape
OSINT Landscape released
This landscape shows the main platforms and tools of Open Source Intelligence (OSINT) and Open Source Investigation (OSINV). OSINT is the collection and analysis of publicly available sources in an intelligence context. "Open" refers to overt, publicly available sources as opposed to covert or clandestine sources..... Read More >....
SIERRA-II
Russian SIERRA-II attack submarine ('Condor') Two titanium-hulled SIERRA-II nuclear powered attack submarines serve with Russia’s Northern Fleet stationed near the Arctic Circle.... 
Single-versus-Double_Hull
Single & Double-hulled submarines demystified
Submarines can be divided into those with a Single Hulls and those with Double Hulls. The former has only one layer of steel between the crew and the open ocean while the latter has an external outer hull which completely encases the occupied inner hull. The relative merits of these two approaches is hotly debated....
USN-SEALs_Jetski
US Navy SEALs' modified jetski revealed
A photo published by the US Navy shows the heavily modified YAMAHA 2016 FX CRUISER SHO jetski... 
Vogo_SDV-1000W
Vogo Engineering's SDV-1000W Submersible boat / Swimmer Delivery Vehicle... 