The S-50 class submarines:
Design: -With the commissioning of the S-43 boats into the CCCN fleet, the admiralty had only temporarily filled a gap. After 3 or 4 years, the navy was hopelessly outnumbered. The S-43 class was far from perfect, and the old submarines that had been modernized after the war were in a run down state and literally falling apart. What was needed was a design with respectable capabilities that could be cheaply produced in local yards. The type was determined as a coastal submarine, since this would suffice for service in the shallow waters of the Caribbean. The boats were to be 58 meters long, and displace upwards of 600 tons when submerged. The program called for 16 boats, all of which were laid down.
Armament: Armament was the most important part of the design, and it consisted of 4 x 21-inch torpedo tubes for different kinds of torpedoes. Among the torpedo load were 8 x locally developed Type 18 anti-surface torpedo, which was wire-guided, and 4 x Type 12 multi-purpose torpedo, which could strike both submarine and surface targets. Four boats were fitted to carry 16 multipurpose mines each, in vertical release tubes aft of the conning tower. These boats were slightly longer than the rest of the class. A pair of decoy launching tubes were carried aft, near the rudder and shafts.
Propulsion: Propulsion was intended to be very fuel-efficient and silent, and consisted of a locally developed powertrain. This arrangement was intended to provide over 800 horsepower, and consisted of two shafts each driven by a 400 horsepower CEB/CNMPA diesel engine driving a 150 horsepower electric motor. This arrangement provided 10 knots of speed while on the surface, and dropped to 6 knots while submerged.
Sensors and Processing Systems: The array of antennas on the sub's conning tower consisted of several different devices. There were thermometers, radio antennas, air and surface-search radars, and other condition-measurement instruments. Two of the periscopes were ready for immediate use in the event of combat. One of the periscopes was a reserve, in case the others were unusable or damaged. A central computer system was also a first for the nation, and consisted of data-processing computers for calculating ballistic information for launching torpedoes. These systems were developed locally by the Antilles High-Performance Machinery Bureau, and were based on a Soviet design. Several processor banks transmitted data to visual monitors, and key information was stored over a network of integrated hard drives and disks.
Construction, Service, and Upgrades: The 16 boats of the class were laid down at 2 different yards. 6 were laid down in Port-Au-Prince in Haiti, with the other 10 at the Arsenal de Havana in Cuba. Building started in 1964, and all were completed by the next year. The commissioning of the boats caught the attention of the USN, but the dismissed them as just another "Third-World propaganda tool." They had severely underestimated the capabilities of the boats, and the gap for the CCCN fleet was filled for at least another 2 or 3 years, until longer-range boats could be constructed. They served mostly quietly, except for some patrols off Nicaragua during the civil war there, after which they were slated for a modernization. In 1981, they all went to the yard to receive more modern observation and optical equipment, as well as the replacement of their data processors and computers with more modern systems. Machinery was also reworked to be more quiet, and facilities for torpedo handling were improved to allow use of the most modern torpedo equipment. As of 2016, 12 of the 16 are in service, with the other 4 being sold for scrapping to provide spare parts for the active fleet.