The illustration below is copied from the Fort Siloso section of a map of 1885 which showed defences on Blakang Mati. The arcs of fire shown for all the 7-Inch RML Guns, cannot be correct. The location of all gun emplacements on the map are incorrect and at variance with evidence on the ground at the fort. The No.1 & No.2 7-Inch Guns were in fact emplaced directly overlooking the harbour. The No 5. Gun was more to the south east. The two 64 Pounders were to the south of the positions shown on the map. More accurate arcs of fire for the 7-Inch Guns are shown in a link on the 1878 - 1918 page. The accuracy of the arcs of fire shown for the 64 Pounders cannot be verified, but is likely to be fairly accurate.
The map is shown to demonstrate that historical records can be inaccurate, and should not always be taken as fact.