3 pounder QF guns were installed on the hulk Loudon, one of a line of hulks which were protecting the East Lagoon, and on the Detached Mole. The guns were probably Hotchkiss types, as shown in the photo on the right. These were manufactured at the end of the 1800s for land service, or possibly a more powerful Vickers made gun from 1910 manufactured for the Royal Navy.
Extracts from Operational Order No.2 dated 12 Nov 39
1. The role of the small craft examination battery will be performed by a 3-pr. gun mounted on the S.E. end of the detached Mole.
4. The detachment consisting of one N.C.O. and 3 men will be found by F.C. Faber. the N.C.O. will not be below the rank of BDR.
10. Communications between the Mole position and the examination vessel will be by the firing of green Verey Lights and voice control. A megaphone will alway7s be available at the gun position.
It was reported on 31 July 1941 that one round was fired from the gun on the Mole, and a request made that, “One man be relieved of his duties at once".
Extract from Operational Instruction No.75 4 Apr 41.
(a) The 3-pr equipment on the hulk LOUDON will be manned by day and night. This necessitates the manning nightly of the associated D.E.L. (NOTE: This gun was manned by 7 Coast Regiment R.A.)
(b) The 3-pr equipment on the MOLE (small craft Examination gun) is being manned by the S.S. R.N.V.R.
(c) The naval armed patrol launch on KEPPEL Harbour boom is being withdrawn.
Extract from Operational Instruction No.78 7 May 41
With effect from 1200 hours 6 May 41 the detachment for the 3-pdr. gun and D.E.L. on Hulk LOUDON will be withdrawn.
These detachments will be at 24 hours notice to man....... When the guns and D.E.L. are manned the primary role of the 3-pdr. equipment will be to protect the boom against damage. Therefore when the gate is closed any vessel approaching the boom can be judged to be potentially hostile and a “bring to” round will be fired.

The Line of Hulks

The Detached Mole
The arc of fire for the 3 pounder on the Loudon was given as being from 45° to 202°. This makes it likely that the Loudon was the southernmost of the line of hulks. The D.E.L. was on a fixed bearing of 188° degrees with an arc of 7½°to each side. In an emergency the stop on the light could be removed enabling the light to cover the complete arc of fire.
A 4 inch gun was planned for the Mole, but this never came to fruition. An August 1941 cipher from G.O.C. Malaya to the War Office proposed a 12 pounder for the Mole, and two more for Tanjong Rhu. In the event, none of these plans were actioned.
The gun on Loudon was reported as being destroyed around 1600 hours on 14 Feb. I’ve no idea what happened to the gun on the Mole.