A major incorporation into the existing defences came with those towers built to protect sluice gates and parts of the Royal Military Canal. The Canal had been dug at great haste after being suggested by Lieutenant-Colonel John Brown in September 1804, and its purpose was to provide a water obstacle to seal off the Dungeness peninsula and Romney Marsh. Running between the River Rother at Rye, to Shorncliffe in Folkestone, the Canal was later extended back from Rye to seal off Pett Level in the same way.
It had originally been planned to flood the entire marsh area upon French invasion, but this was later considered ineffective, as the local populace would have to be evacuated, and it would take several tides to render the area impassable to invading troops. The extent of intentional flooding was later revised.
The Royal Military Canal was the alternative to complete inundation, and Martello Towers were sited to protect vulnerable sluice gates to prevent the French navigating their way inland using such waterways. English control of the sluices meant that saltwater could be introduced into the inland waterways, to deny the French an easy supply of drinking water.
Towers 22 and 23, 24 and 25 (shown right), and 26 and 27 all protected vital sluice gates into the English Channel. Tower 30 protected the Royal Military Canal sluice gates, as well as those of the Rivers Brede and Tillingham. Tower 38 was sited at the end of the Pett Level extension, to prevent the French from outflanking and getting behind the canal. The Martello Towers were to be the first line of defence, control of the sluices would allow saltwater contamination of Romney Marsh to be the second, and finally, the Royal Military Canal was to be the third.
This situation was not to everybody's liking: John Brown had been at the Rochester conference of October, 1804, and disapproved of the Martello scheme because it had been discussed more than his Royal Military Canal. He later wrote:
"The expensive and diabolical system of Tower Defence was finally resolved on to an unprecedented extent...Mr. Pitt, from whom one would have expected a decided opinion, gave into that of others and without requiring, what indeed he would not have obtained, a satisfactory and well-digested plan of defence, all that was advanced was Tower, Tower, Tower; some large and some small was all the variation proposed by the engineers, and when General Morse was asked if he thought even the number of towers would be sufficient, he thought not, but proposed to place cannon between them in open batteries. The tower system appeared in some parts of the coast to be too scanty, in others too profuse. Brigadier-General Twiss, having proposed two towers for the protection of each of the sluices of Dymchurch Wall, being asked if one would not be sufficient for this purpose, said it was highly important to defend the sluices, because at all events they would admit saltwater enough to destroy the fresh, so that, should the enemy land, they would have nothing to drink. This from Brig-Gen Twiss, and the open batteries between the towers from General Morse, are a sufficient specimen of the importance of their remarks."
Although not recognised as such by some, the Martello Towers were an important platform upon which resistance to successful invasion rested. To see how the towers fitted into the overall defence scheme with the Royal Military Canal, first go to the Martello Maps page.