Porpoise

Type	SS
Country	UK
Displacement (t)	2,450
Length (m)	88.0
Beam (m)	8.1
Draft (m)	5.5
Height (m)	8.1
Max speed submerged (kn)	17.0
Max speed surfaced (kn)	12.0
Max safe depth (m)	122
Endurance (days)	50
Diesel-electric	Yes
Titanium hull	No
Class year	1956

Sensors

Sonar (2)

Name	Type	Platform	Passive range (km)	Active range (km)
Type 186	Hull	sub	1.3	—
Type 187	Hull	sub	1.3	1.7

Launchers (3)

Name

Tubes

Fire control

Max launch depth (m)

533mm Torpedo Tube (forward)

6

FCS

100

1962 - 1971: 14 x Mk 20 S , 14 x Mk 8
1972 - 1979: 14 x Mk 23 Grog , 14 x Mk 8
1980 - 1984: 14 x Mk 24 Mod 1 , 14 x Mk 8
1985 - present: 14 x Mk 24 Mod 2 , 14 x Mk 8

533mm Torpedo Tube (aft)

2

FCS

100

1962 - present: 2 x Mk 20 S

Signal Ejector

2

—

305

Individual hulls (8)

Name	Short name	Country	Start date	End date	Remark
S01 Porpoise	HMS Porpoise	UK	1958-04-17 (Commissioned)	1982-01-01 (Decommissioned)
S02 Rorqual	HMS Rorqual	UK	1958-10-24 (Commissioned)	1977-05-05 (Decommissioned)
S03 Narwhal	HMS Narwhal	UK	1959-05-04 (Commissioned)	1977-02-10 (Decommissioned)
S04 Grampus	HMS Grampus	UK	1958-12-19 (Commissioned)	1980-01-01 (Decommissioned)
S05 Finwhale	HMS Finwhale	UK	1960-08-19 (Commissioned)	1988-01-01 (Decommissioned)
S06 Cachalot	HMS Cachalot	UK	1959-09-01 (Commissioned)	1979-11-12 (Decommissioned)
S07 Sealion	HMS Sealion	UK	1961-07-25 (Commissioned)	1987-01-01 (Decommissioned)
S08 Walrus	HMS Walrus	UK	1961-02-10 (Commissioned)	1987-01-01 (Decommissioned)