Plymouth Naval Base & Fortress

Plymouth Naval Base & Fortress

Though Plymouth had been of naval importance since the later Middle Ages, the development of a regular naval base began only at the end of the seventeenth century. Charles II’s Citadel, started in 1667, replaced Drake’s fort with a much larger and better designed defence covering thirty-three acres and mounting some 160 guns to sweep the land and sea approaches; but while the Dutch remained the chief enemy, and the North Sea the main area of naval operations, there was no immediate need for a dockyard. Private shipyards in the Cattewater coped with repairs to naval vessels.

Devon - Plymouth Naval Base
Devon – Plymouth Naval Base

But after the Revolution of 1688, France became the chief threat and remained so for two centuries. In 1686 the aggressively minded Louis XIV began to develop a naval port at Cherbourg, in addition to that already in use at Brest, and an English base further west than Portsmouth was essential. At first there was some idea of choosing Dartmouth, or a Plymouth site at Turnchapel, but in 1691 began the construction of the first dock on the Hamoaze. Extensions throughout the eighteenth century, and the growth of a new naval town, made ‘Plymouth Dock’ larger than Plymouth itself by the time of Napoleon. In 1756 with the outbreak of the Seven Years War, a line of fortifications was begun round the then limits of the dockyard and town; but though further work was done during the Napoleonic Wars, they were not fully completed till the mid nineteenth century. New batteries were built covering the sea approaches during the American war, when com­mand of the sea was temporarily lost in 1781, and several more during the Napoleonic invasion scare of 1804. Not till the 1860s, however, was Plymouth (together with Portsmouth, Chatham and Dover) given serious defences capable of withstanding a siege. The appearance of the ironclad warship at this time, and of new and much more powerful types of naval gun, temporarily wiped out much of Britain’s naval superiority and made Napoleon III’s growing fleet appear more of a threat than it actually was.

Devon - Plymouth Naval Base & Fortress

Palmerston’s defences were designed to prevent the French seizing the Channel Fleet’s bases by a sudden landing circumventing the harbour batteries. The original plan, made in 1859, envisaged more works than were ever built, including six forts and a rampart to cover the approach to Saltash. After Palmerston’s death in 1865 the very different Glad­stone, with his dislike of military expenditure, took over, and the Saltash side was left undefended – leaving a dangerous gap from which the dockyard might have been bombarded. An intended rampart and fort between Scraesdon and Tregantle was also dropped. Most of the major works actually built were ready by 1870, and construction of seaward batteries continued into the 1890s; but the landward defences were never armed with the guns they were intended to mount. Palmerston’s commission had estimated for 742 heavy guns and a standing garrison of 15,000, but this was far too much for Gladstone. The sea approaches were, however, effectively covered without delay by massive casemated forts at Picklecombe and Bovisand, and by the Breakwater Fort – armoured, like those in the Solent, with four layers of thick iron plate with iron concrete between them. The landward forts took the typical form of the time, with vertical ditches covered against assault by fire from caponiers projecting below rampart level at the corners, and counterscarp galleries with mountings for the main armament emplaced in massive ramparts of tipped earth, and magazines and living quarters similarly bomb-proofed. In fact, the decline of French naval power and the effective re-establishment of British naval supremacy after 1870 removed any threat of a major French landing, and justified the refusal to arm the landward forts.

Devon - Plymouth Breakwater

During the eighteenth-century wars, and particu­larly during those of the French Revolution and Napoleon, Plymouth was a vital base for blockading the opposing French coast and ports: but it was never a safe refuge in a southerly gale. Fleets by this time were too large to lie up in the Hamoaze, and would in any case have taken too long to get to sea through the narrow entrance on a sudden alarm.
Admirals often preferred Torbay to Plymouth Sound, but there they were equally exposed to a storm from the east. The only effective answer was to construct an artificial harbour; but the size and difficulty of the project were daunting, and there were conflicting opinions on where it could best be built. In 1806 the elder Rennie recommended a breakwater right in the middle of the Sound, leaving channels at either side which the increased tidal scour would keep clear, but the work was not started till 1812, when the war was nearly over. Three and a half million tons of limestone blocks from the Oreston quarries were ferried out in barges, dumped between buoys marking the line, and left to be compounded into a solid mass by the force of the waves. The work was not finished till 1848, but it was already far enough advanced to be admired by Napoleon when he reached Plymouth as a captive in the Bellerophon after Waterloo. Experience of heavy storms during construction made a more gentle shelving seaward slope on the breakwater necessary, and a ‘foreshore’ was added in front of the crest to break the force of the waves. Finally completed, and cased with squared dovetailed blocks, it proved able to resist all weathers. At last, the Sound was safe with the wind in any quarter.

The awkward period when ships carried steam-engines as well as sail made further dockyard exten­sions necessary, as did later the increasing size of vessels and specialisation into different types. The end of the old rivalry with France, and the outbreak of war with Germany in 1914, transferred the main area of heavy-ship operations back to the North Sea, and robbed Plymouth of much of its value as a battleship and cruiser base. Instead, the devel­opment of submarine warfare against the vital sup­ply lines in the South-Western Approaches gave it a new role in escort and anti-submarine work, which it kept in the war of 1939-45.