Coalhouse Fort is exceptionally well-preserved; it provides one of the finest surviving examples of a mid-Victorian armoured casemate fort.
It has twelve casemates arranged in a semi-circle facing south and east towards the river, with an annexed open battery facing south-west.
The casemates are faced with massive slabs of granite and have iron gun ports to protect the gunners from splinters dislodged by incoming fire.

Although the casemates have been altered over the years, many of their original features survive.
None of the guns remain in situ but the metal rails on which they traversed are still in place.
The casemates were divided into two sections.
During periods of high alert the gun crews would live next to their weapons in the casemates' rear, an area known as the war accommodation.
The front of the casemate was the gun emplacement proper, where the loading and firing took place.
The iron shield protecting each casemate was fitted with iron bars from which two mantlets made of thick lengths of rope were hung.
These protected the gun crew from splinters and smoke.
A loading bar above the gun-port enabled the crew to lift the heavy shells and cartridges up to the mouth of the gun.
These were dispensed from the magazines below via lifts on either side of the emplacements.

The guns mounted in the open battery were lighter than those in the casemates and were not enclosed but traversed on rails in the open air.
A covered section between each emplacement led to an ammunition lift shaft up which the shells and cartridges were raised using lifting gear that still survives.

Improvements to artillery technology necessitated significant changes to the fort's structure towards the end of the 19th century and the start of the 20th.
Closely packed casemates of the type built at Coalhouse Fort were vulnerable to new and more powerful types of explosive shells.
To alleviate this threat, massive concrete traverses were constructed in the 1880s to isolate each casemate, preventing a shell bursting inside one casemate from affecting its neighbours and causing a cumulative explosion.
The construction of concrete gun emplacements on the fort's roof necessitated the installation of circular concrete pillars within the casemates to support the extra weight on the roof.
The ammunition lifts were also extended to serve the new roof-mounted guns.
Coalhouse Fort is exceptionally well-preserved; it provides one of the finest surviving examples of a mid-Victorian armoured casemate fort. It has twelve casemates arranged in a semi-circle facing south and east towards the river, with an annexed open battery facing south-west. The casemates are faced with massive slabs of granite and have iron gun ports to protect the gunners from splinters dislodged by incoming fire.
Although the casemates have been altered over the years, many of their original features survive. None of the guns remain in situ but the metal rails on which they traversed are still in place. The casemates were divided into two sections. During periods of high alert the gun crews would live next to their weapons in the casemates' rear, an area known as the war accommodation. The front of the casemate was the gun emplacement proper, where the loading and firing took place. The iron shield protecting each casemate was fitted with iron bars from which two mantlets made of thick lengths of rope were hung. These protected the gun crew from splinters and smoke. A loading bar above the gun-port enabled the crew to lift the heavy shells and cartridges up to the mouth of the gun. These were dispensed from the magazines below via lifts on either side of the emplacements.
The guns mounted in the open battery were lighter than those in the casemates and were not enclosed but traversed on rails in the open air. A covered section between each emplacement led to an ammunition lift shaft up which the shells and cartridges were raised using lifting gear that still survives.
Improvements to artillery technology necessitated significant changes to the fort's structure towards the end of the 19th century and the start of the 20th. Closely packed casemates of the type built at Coalhouse Fort were vulnerable to new and more powerful types of explosive shells. To alleviate this threat, massive concrete traverses were constructed in the 1880s to isolate each casemate, preventing a shell bursting inside one casemate from affecting its neighbours and causing a cumulative explosion. The construction of concrete gun emplacements on the fort's roof necessitated the installation of circular concrete pillars within the casemates to support the extra weight on the roof. The ammunition lifts were also extended to serve the new roof-mounted guns.
Coalhouse Fort