Light Coastal Forces was a branch of the Royal Navy, formally established in late 1940 during the early period of the Second World War, in response to an emerging threat from the German Navy, known at that time as the Kriegsmarine.

Its distinctiveness as a unit lay not just in its use of motor boats—which included some of the fastest sea-going craft of their day—nor in its varied roles or methods of operation, but in the men who crewed the boats; men who were mostly drawn from civilian life, either as reservists or as volunteers, and who served for the period of ‘hostilities only’ before being discharged back to ‘civvy street’.

The motor boats or ‘little ships’ as they were affectionately known by their crews, were in sharp contrast—in terms of scale—to the regular ‘big ship’ navy of major warships, and the close camaraderie enjoyed by the men of these tight-knit fighting units was to prove a defining characteristic of Coastal Forces.

First World War

Though no distinct branch named Coastal Forces existed during the earlier 1914–1918 conflict, the large scale use and deployment of purpose-built fast motor boats began at this time.

During the First World War the unrestricted use of submarine and mine warfare constituted a grave threat to shipping, particularly in the English Channel, where millions of men and their supplies were required to be transported by sea to France throughout the period of the war.

In response to the growing menace posed by these modern forms of warfare, an irregular assortment of boats including private yachts were drafted into service in support of the regular navy as part of the Auxiliary Patrol, before more effective solutions to tasks such as submarine chasing were sought in the form of purpose-built motor launches built by the American company Elco.

A force of some five hundred and eighty of these motor launches were built by Elco, augmented by faster boats called Coastal Motor Boats (CMBs). The CMBs were designed and built by the British manufacturer Thornycroft to carry torpedoes as part of an offensive capability. The use of motor boats on this scale mostly crewed by reservists served as a blueprint for the later Coastal Forces.

Armistice and the Peace

Following the defeat of Germany in 1918 and the signing of an Armistice which expressly forbad Germany the “construction or acquisition of any submarine”, most of the Motor Launches and Coastal Motor Boats together with the knowledge and experience their crews had acquired during that period were disposed of, in favour of a peace dividend, and the focusing by senior officers once more on capital ships.

Though the experience of the officers and men passed into and was held in the reserves, and although manufacturers such as Vosper and British Power Boat continued to evolve the design of fast motor boats in a non-military context for private buyers; momentum in development of the military use of such boats, together with the organisational know-how required for their use, was effectively lost at this point.

The Inter-war Years

The Admiralty did not look again at the concept of the fast motor boat until the 1930s, when the prospect of war with Germany and Japan, in what they considered would be the following decade, looked increasingly likely. They began to weigh up designs for a new generation of motor torpedo boat from power boat manufacturers of the day such as British Power Boat under Hubert Scott-Paine, and Vosper under Peter Du Cane.

The slow pace of development however did not see any new boats commissioned until 1936, and although the Admiralty may have signalled their intent to rebuild forces in the long-term, military marine development during this period lagged behind the evolution in aeronautical design of fighter aircraft such as the Spitfire, whilst training for navy personnel in the tactical use of fast motor boats, and overall command & control structures, were poor or non-existent.

The Legacy of Neglect

This comparative neglect of fast motor boat capability was to be lamented by some involved in their later use during the Second World War, who faced an uphill struggle at that time to re-establish the kind of training & support network needed to tend to such high-maintenance craft.

Those involved in the early formation of Coastal Forces were to find themselves doing battle at sea in boats that proved underpowered and poorly armed, in comparison to an enemy whose boats had enjoyed continuous development throughout the decade leading to war.