Nine submarines, three of them belonging to the Tench class, were upgraded from GUPPY II to GUPPY III in 1959–63 as part of the Fleet Rehabilitation and Modernization II (FRAM II) program.
All except the Balao-class Tiru, the pilot conversion, were lengthened by 15 feet (4.6 m) in the forward part of the control room to provide a new sonar space, berthing, electronics space, and storerooms.
Tiru was lengthened only 12.5 feet (3.8 m), and both forward diesel engines were removed.
The other GUPPY IIIs retained all four engines.
A taller "Northern" sail was included for improved surfaced operations in rough seas; this was also backfitted to some other GUPPY and Fleet Snorkel boats.
The BQG-4 Passive Underwater Fire Control Feasibility Study (PUFFS) sonar system, with three tall domes topside, was fitted.
Additionally, fire control upgrades allowed the Mark 45 nuclear torpedo to be used.
Nine submarines, three of them belonging to the Tench class, were upgraded from GUPPY II to GUPPY III in 1959–63 as part of the Fleet Rehabilitation and Modernization II (FRAM II) program. All except the Balao-class Tiru, the pilot conversion, were lengthened by 15 feet (4.6 m) in the forward part of the control room to provide a new sonar space, berthing, electronics space, and storerooms. Tiru was lengthened only 12.5 feet (3.8 m), and both forward diesel engines were removed. The other GUPPY IIIs retained all four engines. A taller "Northern" sail was included for improved surfaced operations in rough seas; this was also backfitted to some other GUPPY and Fleet Snorkel boats. The BQG-4 Passive Underwater Fire Control Feasibility Study (PUFFS) sonar system, with three tall domes topside, was fitted. Additionally, fire control upgrades allowed the Mark 45 nuclear torpedo to be used.
Tench-class submarine