Speed (knots): 19 (submerged)
Number in class: 4
Users: Italy
Comments: Basically improved versions of the Enrico Toti boats that preceded them. Nice little boats designed for operations in the narrows of the seas surrounding Italy.
Class name: S 90
Producer (country/manufacturer): Italy/Fincantiere
Displacement (surfaced/submerged): 2,500/2,780
Dimensions (ft/m): Length: 228.6/69.7 Beam: 26.7/8.2 Draft: 20.7/6.3
Armament: Six 533mm torpedo tubes with 24 weapons
Machinery: Diesel-electric drive with one 7-bladed screw;? SHP
Speed (knots): 19 (submerged)
Number in class: 0 + 2
Users: Italy
Comments: Follow-on to the Primo Longobardo class. Design differences include greater endurance and depth capability. Design not finalized, and changes could occur.
Glossary
1MC Main shipwide announcing circuit on U.S. submarines.
ADCAP ADvanced CAPability. Newest version of the Mark 48 torpedo on board U.S. submarines.
AFFF Aqueous Fire Fighting Foam.
Akula SSN A third-generation Russian design competing with the Sierra I and II classes, the Akula appears to be the overall winner. This boat is very quiet, equivalent to a U.S. Flight I 688, and is equipped with acoustic and nonacoustic sensors. Largest SSN class in production. How large the class size will be is unknown, but at present there are seven Akulas in the Russian inventory.
AN/BPS-15A Navigation radar on many U.S. SSNs.
AN/BQQ-5 (A-E) Integrated sonar suite on most U.S. SSNs. The different variants include improvements in signal process and/or different sonar arrays.
AN/BSY-1 Integrated sonar and fire control system on Improved Los Angeles-class SSNs.
AN/WLR-8(V)2 Radar warning receiver on 688I-class SSNs.
AN/WLR-9 Acoustic intercept receiver found on U.S. Navy submarines.
AN/WLR-10 Radar warning receiver with recording capability on 688-class SSNs.
Anechoic coating Rubber coating applied to the exterior hull surfaces of a submarine to absorb active sonar pulses. Reduces the detectability by active sonars. Some coatings also reduce the amount of noise a submarine puts into the water; these are called decoupling coatings.
Angles and dangles Test conducted by a submarine to ensure that everything is stowed properly before beginning its mission. The procedure calls for making large up-and-down movements with the submarine as well as using large rudder angles at moderate speeds.
ASDIC Allied Submarine Detection Investigation Committee. Formed during World War I (1914-18) to conduct research and experiments on submarine detection.
ASW AntiSubmarine Warfare.
AUTEC Atlantic Undersea Test and Evaluation Center. An acoustic test range located off Andros Island in the Bahamas.
Bastions Highly defended SSBN patrol areas. Established by the former Soviet Union, now used by Russia to protect their SSBNs from attack by Western SSNs.
Blue/gold crew The policy of having two alternating crews aboard strategic missile submarines.
BOL (Bearing Only Launch) Launch mode for Harpoon and Tomahawk antiship missiles that doesn't require range information. Essentially the missile seeker is activated once cruising altitude is reached.
Bomb shop Royal Navy term for the torpedo room on submarines.
Bombers Royal Navy nickname for strategic missile submarines.
Boomers U.S. Navy nickname for strategic missile submarines.
Bottom bounce Term used to describe the route taken by sound waves as they bounce off the ocean bottom traveling from the noise source to the sonar receiver. For example, the noise source could be an active sonar pulse that bounces off the bottom and hits the target ship; then the echo bounces off the bottom again and is received by the sonar.
Breech door Inner door of a torpedo tube.
Bridge Small observation area on top of the fairwater. The OOD stands his watch here when the submarine is on the surface.
Buttercup U.S. Navy term for the 'wet' or flooding trainer.
Cavitation The formation of tiny vapor (air) bubbles on the surface of a propeller when the propeller moves through the water rapidly. Cavitation is a source of very loud noise.
CENTCOM U.S. CENTral COMmand.
CH 084 Multifunction attack periscope on Royal Navy SSNs.
Choke point Geographical restriction that limits the maneuverability of a ship or submarine.
CIS Commonwealth of Independent States (formerly the Soviet Union).
