Site Records

Site Name: Hoo Fort

Medway Estuary
North of Gillingham
Kent
OS Grid Ref: TQ797703

Sub Brit site visit 9th September 2007

When building restarted the design had been altered to accommodate the different soil conditions. One of the changes called for the magazines to be placed nearer the outside wall instead of the centre as was originally planned, as it was thought that this would spread the load more evenly. Unfortunately this caused even greater problems, for when the building had reached eleven feet at Hoo and between eight and nine feet at Darnet, cracks began to appear in the masonry. The cracks at Hoo continued until further measures were taken. These included the pouring of 3,500 tons of ballast into the centre of the fort (where the magazines were to have been placed). The forts were then surrounded by concrete skirts, which were to serve two purposes; firstly a glacis was formed (a defensive slope); secondly, the concrete skirt stopped the surrounding soil from being pushed up by the weight of the structures.

Drainage was yet another problem, as was shown dramatically when a well was sunk into the concrete of Hoo Fort. The concrete was still saturated and was so porous that the well had to be pumped continuously at the rate of 4,500 gallons an hour for a considerable time. To counter this it was decided to drain the land with a siphon arrangement of pipes and wells. This apparatus was kept in use for several years until the ground had dried out.

9" RML - this example is at Needles Battery, Isle of White - Photo from Palmerston Forts Society

In 1867 a revised plan for the forts was approved. Instead of the planned three-tiered buildings, the forts were to be limited to two tiers. Each fort was to have eleven guns, whereas the original design had planned for twenty-five. The new armament was to be eleven 9-inch rifled-muzzle loading (RML) guns at Hoo with eight 9-inch RML’s and three 7-inch RML’s at Darnet - half the number of the original plan, yet the fire-power in terms of accuracy, rate of fire and weight of shot was superior. The forts were commissioned in 1871

The structures can be divided into three main parts: the lower floor housing the accommodation casemates; the upper floor carrying the guns (with the gun casemates doubling as extra accommodation in an emergency), the third part, in the centre of the fort being a structure shaped like a drum. This drum carried a stairway from ground level to the gun floor, the space between the drum and the guns being spanned by narrow bridges. This part of the building was also used as the parade ground. Entry to the fort is through a gateway over a drawbridge covering a pit between two sets of gates. This area is also covered by two musket loopholes on either side. At Hoo a geared winding device with counterweights was employed to lift the drawbridge.

The accommodation casemates seem to have been quite spacious, for although the forts were designed for a garrison of 100 men each, there seems little likelihood that there would have been more than 25 to 30 men in peace-time. The accommodation casemates all have fireplaces with a grille set high in the wall for heat to be convected from around the fire.  The latrines are still well preserved, being served with rainwater, collected from the roof via ducts and gutters leading to two large water tanks in the central drum of the building, the material used in the making of the latrines was thick slate - there is still a well-preserved slate bath in position at Hoo. One of the casemates has a large stove in place of the fire and this room was probably the messroom, another casemate contains handbasins and ovens.

The ammunition was divided and stored in two different sets of rooms. Guns number 2-8 had one room each for shells and one room each for cartridges; whilst guns 9 and 10 shared facilities, as did guns 1 and 11 - though these store rooms were for the landward-facing guns. The cartridges and shells were brought together in a small room opposite the magazines and these were pulled up by means of a hoist to the gun floor. The magazines were lit in an unusual way, to ensure that no naked flame came into contact with the stored ammunition; each magazine has its own independent lighting passage, a small wooden-floored lighting room parallel to the ammunition passage which joined all the magazines. From the lighting room the ammunition shafts at each end could be lit from a glass sealed alcove in the wall. The magazine was lit by a lantern on a trolley and with the aid of a winching mechanism; the trolley was guided along the top of the ammunition passage into a glass fronted alcove in the magazine. The rail above the top of the passage was sealed in a zinc casing. The fumes from the lanterns were withdrawn from the alcoves by means of a flue set into the alcove ceiling which came out in the lighting room.

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