As a coastal fortification the design and organisation of the Fort is typical of others built around the British Empire in the 1870s and 1880s. It uses the flexibility of mass concrete to create massive but sinuous curved shapes, and a complex juxtaposition of straight lines and curved forms on differing levels. These are functional spaces and lines, linking the circular gun emplacements, and the curving gun passage with the regularity of the Barracks and loopholed rear walls. In plan the Fort is essentially symmetrical, in two main levels, accessed by ramps and stairs. The view from seaward, to the east, is primarily of natural surfaces and contouring, with few hard lines except for the casemate gun shield. The predominant features that create Bare Island are low relief, a juxtaposition of natural and concrete surfaces, scale and mass. Bare Island is significant as the only island in Botany Bay. The construction of the form is aesthetically pleasing for its close relationship and integration with the natural island landform with the built form. The visible built work provides an indication of the massiveness of the concealed construction. It is a nationally representative example of the corpus of significant designers of fortifications – Jervoise and Scratchley, a regionally representative example that demonstrates fortification design in the late 19th century, and regionally representative as an example in the evolution of the design of coastal fortifications.