Yes Mossie that is correct but 11inch and 6 inch gun crews Fort Siloso did fire on fuel tanks and refinery and assisted the infantry defending Singapore. Unfortunately not all batteries had HE but armour piercing hence the MYTH. But Fort Siloso did fire inland towards Singapore and you definitely do not need armour piercing to destroy and oil refinery and assist infantry. there were more G
Gun Emplacements than Fort Siloso of course Mossie. There were gun emplacements all around Singapore Harbour of course
Fort Siloso: Other Defences link you can check the other locations of gun batteries around Singapore