HMS B4: An Early B-Class Boat That Guarded the Dover Straits

The Build: Barrow-in-Furness

HMS B4 was built at the Vickers shipyard in Barrow-in-Furness, launched on 14 November 1905 and commissioned on 28 January 1906, one of eleven B-class submarines built for the Royal Navy in the first decade of the twentieth century, small early boats displacing just 287 tons on the surface and 316 tons submerged, armed with two 18-inch torpedo tubes in the bow, crewed by only two officers and thirteen ratings.

An Early Collision

Just months into her career, B4 collided with a dredger while entering Portsmouth harbour on 21 July 1906, suffering significant damage that required repairs in dry dock, an early reminder of just how hazardous even routine harbour manoeuvres could be for these primitive early submarines.

Guarding the Straits of Dover

When war broke out in 1914, B4 was assigned to help defend the Straits of Dover, one of the most strategically vital and heavily trafficked stretches of water in the entire war, essential to keeping the English Channel closed to German shipping and submarines throughout the conflict.

Surviving the War

HMS B4 survived the First World War intact, a genuine achievement for a submarine of her vintage and design, before being sold for breaking up on 1 April 1919 to the Ardrossan Dry Dock Company, bringing to a close the career of one of the Navy's earliest and hardiest little submarines.