Project 641B Som

Project 641B

NATO: Tango

Type	SS
Soviet designation	PL
NATO reporting name	Tango
Country	USSR
Displacement (t)	3,546
Length (m)	90.2
Beam (m)	8.6
Draft (m)	5.7
Height (m)	8.6
Max speed submerged (kn)	15.5
Max speed surfaced (kn)	14.0
Max safe depth (m)	240
Endurance (days)	80
Propeller	3 x 6 bladed propellers
Diesel-electric	Yes
Titanium hull	No
Navigation system	Most-641B (Inertial Navigation System)
Class year	1973

Sensors

Sonar (8)

Name	Type	Platform	Passive range (km)	Active range (km)
MG-25	com	sub	—	—
MG-43 Gorizont	ssp		—	—
MG-519	Mine detection	sub	—	1.5
MGK-400 Rubikon Active	Hull	sub	—	4.7
MGK-400 Rubikon Cylindrical	Cylindrical	sub	2.1	—
MGK-400 Rubikon flank array	Flank	sub	2.1	—
MGK-400 Rubikon OGS	Active Intercept		—	—
NEL-5	Echo sounder	sub	—	—

Radar (3)

Name	NATO name	Air search	Surface search	Fire control
MRK-50 Kaskad		—	Yes	—
MRP-25 ESM		—	—	—
Zavesa-P		—	—	—

Launchers (2)

Name	Tubes	Fire control	Max launch depth (m)
533mm Torpedo Tube (forward) 6 MVU-110 Uzel 250 1973 - 1979: 6 x 53-65K , 6 x SAET-60M , 12 x SET-65M 1980 - present: 6 x 53-65K , 6 x SAET-60M , 6 x SET-65M , 6 x USET-80
Signal Ejector	2	—	100

Extendable devices (8)

Name	NATO name	Capabilities	Max depth (m)	Max speed (kn)
MRK-50 Kaskad Radar	—	Radar	—	7.5
MRP-25 ESM	—	ESM	—	7.5
PA-10 Attack periscope	—	Periscope (attack)	—	7.5
PZN-10 Search periscope	—	Periscope (observation)	—	7.5
RDP	—	Snorkel	—	7.5
Topol Radio Antenna	—	Radio (VLF), Radio navigation	—	7.5
VAN Radio antenna	—	Radio (LF, MF, HF), Radio navigation	—	7.5
Zavesa RDF	—	Direction finder	—	7.5