which would be more suitable for PN 054 or 054A?
this might be off topic: I have seen that Indian Naval combatants have anti-submarine rocket launchers mostly RBU-6000, what is the allied equivalent of this, and are they really effective given a range of just 6 km, why would submarine come so close?
Traditionally, Russians employed large heavyweight torpedos (533mm) for ASW whereas Western navies used Lightweight ASW torpedoes (324mm). The RBU is a close-in backup to those heavies and usefull in shallow waters or - with a different rocket - as hard-kill anti-torpedo weapon (UDAV). Western navies have tended to employ a Nixie torpedo decoy instead. In contrast, PLAN uses lightweights for ASW in combination with bow mounted ASW rockets.
Most torpedoes used by subs don't have long range and are used close in. Below some maximum ranges.
Russia (max range at high speed)
SAET-60: 14,200 yards (13,000 m) / 42 knots
SAET-60M: about 16,400 yards (15,000 m) / 40 knots
53-65: 18,000 metres (20,000 yd)
53-65K: 19,000 metres (21,000 yd)
53-65M: 22,000 metres (24,000 yd)
Test-71:
16,400 yards (15,000 m) / 40 knots
27,300 yards (25,000 m) /35 knots
Russia / USSR Post-World War II Torpedoes
UK
Spearfish:
1981 version: About 23,000 yards (21,000 m) / 60+ knots
1994 version: Range unknown / 80+ knots
Tigerfish:
23,000 yards (21,000 m) / 35 knots
about 30,000 yards (27,400 m) / 24 knots
British Torpedoes after World War II
USA:
Mk48
38 km at 55 kt
50 km at 40 kt
USA Torpedoes since World War II
Germany
DM2
A-3: 22,000 yards (20,000 m) / 35 knots (lower speed setting for increased range)
A-4: 55,000 yards (~50,000 m) max range / 50 knots max speed (different speed/range settings)
SST-3
24,000 yards (22,000 m) / 35 knots
56,000 yards (51,200 m) / 23 knots
SST-4
12,000 yards (11,000 m) / 35 knots
22,000 yards (20,000 m) / 28 knots
40,000 yards (37,000 m) / 23 knots
SUT
13,100 yards (12,000 m) / 35 knots
30,600 yards (28,000 m) / 23 knots
German Torpedoes Post World War II
At long ranges, ship tend to use helicopters with lightweight ASW torpedoes anyway.