HMS B5 was one of 11 B-class submarines built for the Royal Navy in the first decade of the 20th century.

[1] For surface running, the boats were powered by a single 16-cylinder 600-brake-horsepower (447 kW) Vickers petrol engine that drove one propeller shaft.

[1] On the surface, the B class had a range of 1,000 nautical miles (1,900 km; 1,200 mi) at 8.7 knots (16.1 km/h; 10.0 mph).

They could carry a pair of reload torpedoes, but generally did not as they would have to remove an equal weight of fuel in compensation.

[3] B5 was built by Vickers at their Barrow-in-Furness shipyard, launched 14 November 1905 and completed 25 February 1906.