Jervois recommended a small work in Botany Bay as protection from small squadrons of hostile cruisers making lightning raids on Sydney and holding it to ransom for its gold reserves. Scratchley was responsible for turning Jervois's strategic vision into a detailed design and specification of the works. This he did with the aid of civil engineer Gustavus Morell. The specifications were also developed with the aid of the Colonial Architect James Barnet who was responsible for its construction. Construction of Bare Island fort was completed in 1885 at a cost of A£34,000; work inside the fort began in 1889.