These boats were built to a French Schneider-Laubeuf design, their French ancestry being obvious in the shape of the hull.
The Admiralty eventually decided against the French design after a visit to Toulon, though an order for four boats was given to Armstrong to keep an agreement to order two boats a year from them.
The class name was derived from the builders name (Whitworth). Being complete failures as they were best suited for service in the Mediterranean the boats were sold to the Italian Government in 1916.
Only W.1 and W.2 actually served in the Royal Navy, they were allocated to the 10th Flotilla in the Humber from 1915 to 1916. The Italians discarded both boats in September of 1919.
W.1 (Commanded by Lt. H.D. Gill) Served with the Second Flotilla based on H.M.S. Dolphin at Portsmouth from December 1914 to March 1915. She was transferred to the Sixth Flotilla based on H.M.S. Bonaventure in the Humber from March to June 1915 when she was again transferred to the 10th Flotilla on H.M.S. Forth at Devonport where she joined W.2. They stayed with the 10th Flotilla until August 1916 when they was sold to the Italians.
2 Electric Motors 480hp.
8.5 kts sm
4 x 18 inch in external drop collars.