were only protected by a forward-facing gun shield. This was done to save weight, as placing additional armour around the guns would have increased the vessel's displacement. These were flaws with the design, as the gunners were left exposed in battle and the gun layout prevented their full use. Modifications Shortly after entering service Java and Sumatra were fitted with aircraft and handling derricks for two Fairey IIID aircraft purchased in 1924. However, the Faireys proved to be too fragile for service in the Dutch East Indies and were replaced in 1926 with Fokker C.VII-W floatplanes. During a major refit in 1934–1935 the two cruisers had their pole foremast replaced with a tubular one that had a director tower atop with a searchlight platform. The mainmast was cut down and repositioned and the searchlights rearranged. Furthermore, the 75 mm guns were landed and replaced with six single-mounted Bofors Mk III guns in Sumatra and eight in Java for anti-aircraft warfare. The new guns were fitted on the aft shelter deck. Additionally, four machine guns were added. Construction The production of two cruisers was authorised on 15 July 1915 as part of the 1915–16 Dutch military programme. The design was completed in 1916 and orders were placed with the keel of the first ship of the class, Java, laid down on 31 May 1916 at the Schelde naval shipyards. The second ship, Sumatra, was laid down on 15 July 1916 at Nederlandse Scheepsbouw Maatschappij in Amsterdam. A third ship, Celebes, was ordered to a modified design on 14 June 1917 from the Wilton-Fijenoord shipyard in Schiedam. All ships were named for islands in the Dutch East Indies. However, construction was delayed due to a series of issues. Material shortages following the end of World War I, labour issues, political interference in the construction all led to delays. Furthermore, there was a serious fire that destroyed Celebes original Germania turbines and required their replacement with Zoelly-pattern versions. The construction of Celebes was cancelled after the budget for the third ship was delayed and her design was found to be obsolete. Only of material had been prepared for Celebes construction and what had been built was broken up on the slipway. Despite the required replacement of her machinery, Sumatra was the first to launch on 29 December 1920. Java followed on 9 August 1921. However, Java was the first to commission, entering service