G Class armament being changed to two 18-inch bow tubes, two 18-inch beam tubes and one 21-inch stern tube. This signalled the beginning of the 21-inch torpedo in Royal Navy submarines, although the experimental submarine Swordfish - ordered from Scotts a year earlier, but launched after G1 - was also fitted with 21-inch tubes. The class also carried one 3-inch Quick Fire High Angle (QF HA) gun which was fitted just forward of the bridge and a portable 2-pounder which could be fixed to a pedestal at the after end of the bridge.
Living conditions on board were considered by crew members to be good - because the G boats boasted such luxuries as an electric oven!
Although the designed diving depth of the G Class was given as
