HMS G4 was a G class submarine built for the Royal Navy at Chatham Dockyard.


The G Class sister-boats were intended to be an improvement over the highly successful E Class. As well as featuring such luxuries as an electric oven in the galley, they also incorporated technological advances over previous vessels. The G Class featured a double-hull, where the ballast tanks were located in the gap between an inner pressure hull and an outer hull rather than saddle tanks mounted on the boat's sides. This makes for a more streamlined, stronger hull with more internal space but is more complex, time-consuming and therefore expensive to build. As a result, only 14 G Class submarines were built rather than the almost 60 of the previous E Class.


The G Class submarine:





HMS G4 was laid down on No 7 slip on 12th October 1914 and was launched into the River Medway by Lady Darnley from there on 23rd October 1915. After fitting out, she was commissioned on 3rd February 1916.


As completed, HMS G4 was 186ft long, 22ft 8" wide across the beam and displaced 693 tons on the surface and 873 tons dived. Originally intended to carry the 21" torpedo tube, one at each end, experience showed that two bow torpedo tubes gave a better chance of success, but two 21" bow tubes would have made the bow of the boat too heavy, so instead they were fitted with a pair of 18" torpedo tubes in the bow. G Class submarines were also fitted with an 18" torpedo tube on each beam but had a 21" torpedo tube in the stern. In addition to this, she had a 12pdr (3") gun forward of the conning tower and a 2pdr (40mm) gun aft of it. She had a crew of 30 men.


HMS G4 running on the surface





After commissioning, she was sent to join 11th Submarine Flotilla at Blyth with Lt-Cdr John Hutchings in command. At some point between 20th August 1916 and 3rd October 1916, she went to Scapa Flow and left there to go to Murmansk (then called Romanov), arriving on 20th October 1916. She left there on 15th November, arriving in Kirkwall five days later.


HMS G4 then spent the rest of the First World War conducting war patrols in the North Sea from Blyth and was there at the end of the war.


HMS G4 and HMS G10 alongside the depot ship HMS Titania





After the war ended, she was transferred to Portsmouth and spent the rest of her career there. Unlike most of her G Class sister-boats, HMS G4 was retained by the Royal Navy into the 1920s. She was decommissioned and put up for sale on 18th September 1926 and was sold for scrap on 27th June 1928 to Cashmore of Newport.