The Polish Blotniak is the only single seat enclosed SDV (Swimmer Delivery Vehicle) ever seriously developed. 
Originally posted 22nd Oct 2014
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CIA_Water-Air_1958
Overview of CIA Water-Air Division equipment, 1958 
This is a summary and analysis of a CIA booklet from 1958 (now declassified with redaction) covering ”Equipment and/or Test Reports Available for Operational use or Planning”. It was compiled by the CIA Water-Air Division who were the Cold War evolution of the Wartime OSS Maritime Unit. Read More >....
Spy Subs - X-RAY
Russian X-RAY Class Special Mission submarine 
The Russian Project 1851 Nelma class (NATO: X-RAY class) midget submarine is shrouded in secrecy. Read More >....
Swedish_Sub_Incursions_RYAN
Swedish news article on Cold War imcursions 
This morning’s Blekinge Lans Tidning (BLT) newspaper ran a story on the Swedish Cold War submarine Incursions. Retired Naval Officer Nils-Ove Jansson drew parallels to when Soviet Spetsnaz combat swimmers came ashore in Sweden to reconnoiter the placing of nuclear mines (allegedly). An interesting article in a few ways... Read More >....
Unbuilt_Russian_Spy_Subs
Multifunctional underwater station (MPS) In 2010 the Russian Ministry of Industry and Trade patented a ‘Multifunctional underwater station (MPS) (Russian: Многофункциональная подводная станция (МПС). Two years later Russian submarine design bureau Lazurite proposed the same design for a range of underwater engineering tasks. Although presented as a civilian platform the design gives us good insight into the Russian ‘deep station’ spy submarines operated by GUGI (Main Directorate of Deep-Sea Research, Military Unit 40056)... Read More >....
DGSE_SDVs
French Secret Intelligence Agency's unknown minisubs 
The World’s national intelligence agencies rarely reveal their submarines. France’s DGSE (Direction générale de la sécurité extérieure - English: General Directorate for External Security), equivalent of the CIA and MI6, is unusual in having its own pool of combat swimmers (Nageur de combat). As well as having access to French Special Forces’ Swimmer Delivery Vehicles (SDVs) they have been equipped with their own unique lineage of SDVs.
... Read More >....
South African Riverine Assault Boat
Originally posted 5th September 2016
Images have emerged of the new South African riverine assault boat in service. Two boats were acquired under Project Carol, joining the SA Navy MRS Operational Boat Division... Read More >....
Explosive_boats
A brief history of Explosive Boats 
The recent attack on a Saudi frigate off Yemen by Houti rebels using a remote controlled explosive boat brings these craft into focus. There have been a lot of different explosive boats developed over the years although few are well known. They are not only used by non-State actors and their history is actually closely intertwined with the minisubs used by Naval Special Forces... Read More >....
Taiwanese_midget_sub
Taiwanese 130 ton Special Forces midget submarine design
The recent uncertainty of US foreign policy regarding the sovereignty of Taiwan (Republic of China) reminds us the Taiwanese Navy’s embattled acquisition program. In 2014 the HARD ROC 2.0 report by the US Strategic and Budget Assessment Center recommended that Taiwan instead concentrate on building a large fleet of some 42 midget submarines. This 350 ton design is most likely in response to this.... Read More >....
SEALION and Alligator stealth boats
SEALION Combatant Craft Heavy (CCH) Various ‘stealth boats’ have been trailed by Naval Special Warfare (NSW, now part of USSOCOM) for use by the Special Boats Units and SEALs. Although always under the radar, several types have been noticed by bystanders over the years. More recently USSOCOM has sought to operationalize the SEALION family of semi-submersible ‘stealth boats’ as the Combatant Craft Heavy. This article builds on the popular post on the old Covert Shores Blog.Read More >....