[1] The fort's main armament consisted of two BL 6 inch Mk XI naval guns.

In the 1860s Queensland established a number of volunteer defence units, based on the British model, but their effectiveness was severely impaired by a lack of armaments and ammunition.

In 1877 the colonial governments of New South Wales, Queensland, Victoria and South Australia, anxious to secure the land defence of their coastlines, jointly invited British Royal Engineers Colonel Sir William Francis Drummond Jervois and Lieutenant-Colonel Peter H Scratchley, to inspect existing defence installations and make recommendations as to how these might be improved.

Jervois and Scratchley identified maritime attacks as the greatest threat to Australia, and recommended that coastal defences be developed for all the mainland colonies.

Despite being physically closer to the source of most threats, Queensland, with its sparse population and limited resources, was not considered to be greatly at risk.

In his August 1877 preliminary report on Queensland coastal defences, Jervois identified the principal threat to Queensland security as an attack from the sea on the major ports (Brisbane, Rockhampton and Maryborough), in the form of city bombardment to secure supplies and coal, rather than for permanent occupation.

[1] As events in Europe and Asia in the 1930s moved the world towards war, various sectors of Australia's defence, including coastal fortifications, were examined.

As major cities and ports along the coastline would be exposed to damage from naval raids or attack, coastal defences were to be upgraded.

Invasion was not a major concern at this stage, rather the batteries were for defence against seaborne shelling or the torpedoing of ports.

Military experts were supporting the implementation of more mobile defence forces, as opposed to fixed facilities.

This dictated the ideal positions for artillery batteries, with the most effective sites for guns being the closest points to the channel bends.

The site included the installation of a reticulated water and sewerage system, which was unusual for the time considering the majority of the greater Brisbane area was not sewered until the 1960s.This seems to be related to a hygiene report on the site during construction of the fort which recommended the system for reasons of maintenance costs and adherence to modern sanitary practices.

The function of the Examination Service was to identify and ascertain the character and intentions of vessels seeking to enter defended ports.

[1] The first real indication of enemy naval presence in proximity to Brisbane occurred on 24 March 1942 when a suspected Japanese submarine was sighted east of Stradbroke Island.

On 14 May 1943, the Australian Hospital Ship Centaur was struck and sunk off the Brisbane coastline by the Japanese submarine, "I.177".

The last attack to occur in the approaches to the Port of Brisbane, took place on 4 June 1943 off Cape Moreton when the Japanese submarine "I.174" fired on the American ship MV Edward Chambers.

With the reassessment of Australia's defensive arrangements in the 1950s, the role of artillery batteries in coastal defence diminished.

The government recognised that the nature of modern warfare had changed and fixed coastal defences were no longer considered a necessary part of defensive plans.

The two gun emplacements remain in situ on the beach although over the years the tide line has moved progressively closer to them.

[1] The site comprises a number of structures, all built in 1937, including two gun emplacements, concrete paths, four magazine huts, foundations of kitchen and soldiers' mess, storage hut, engine room, underground sewerage and piping and a concrete tank.

Fort Cowan Cowan demonstrates uncommon surviving evidence of a largely intact and interpretative Second World War battery complex which incorporates a number of structures including two gun emplacements, concrete paths, four magazine huts, foundations of kitchen and soldiers' mess, storage hut, engine room, underground sewerage and piping and concrete tanks.

It has the potential to yield information that will contribute to the understanding of Queensland's history due to the extensive remnants of Second World War fortification sites, which includes both Army and Naval defences.

Fort Cowan Cowan is important in demonstrating the principal characteristics of Australia's Second World War coastal defence fortifications including 6-inch (150 mm) Mark X1 batteries modified to suit the terrain with emplacements being constructed of reinforced concrete with magazines to the rear of the gun platform rather than below.

[1] The place has a special association with the life or work of a particular person, group or organisation of importance in Queensland's history.