top of page
03 - Bickley Battery - CD Bop & CASL Directing Station

Bickley Battery - CDBOP & CASL
Directing Station

Whilst a Battery Observation Post was already located on Lookout Hill, approximately 1.2km west of the Bickley Battery, the CDBOP was manned by the Gun Position Officer at night. This was largely a result of the decreased visibility at night, compounded by the limited searchlight illumination range of not more than 7.3km.

The Control Tower

The control tower for the CDBOP was located on the first floor of the northern side of the building, with uninterrupted 360 views of the Rottnest landscape.


The CASL Directing Station was located on the southern side of the building on the ground floor level. The Battery Commander could issue orders to the Search Light Officer via a four-inch voice tube, which targets were to be illuminated (The Coast Defences of Western Australia, R. K. Glyde 1991).

Depression Range Finders (DRF)

Two instrument pillars were located inside the CDBOP, both with Depression Range Finders enabling coverage of 360 degrees.

Depression Range Finders, also known as Depression Position Finders, were described as being like a telescope on a base. They were used to determine a target's position by measuring the distance, which was done upon sighting a target, reading a scale and working out the range of the target. The calculations were built into the scales and gearing of the instrument, configured upon installing the DRF at the site it is intended for. This was then transferred by dials onto the guns.

2014 Refurbishment

In 2014, Stantec Pty Ltd was awarded the $1.8 million contract to refurbish the Coastal Defence Battery Observation Post & Coastal Artillery Search Light Directing Station.

Whilst maintaining the integrity of the original structure, their structural team:

  • treated the steel

  • installed new reinforcements

  • repaired the concrete

  • replaced the glass

  • refurbished the masonry and

  • carried out steel preservation treatment to the blast-resistant doors in order to main the original painted signage.

Due to the potential risk of a collapse in the roof, the concrete was refurbished to treat the extensive spalling and corroded steel reinforcements.

The Experience

The CDBOP was pleasantly limited with graffiti and wall carvings, aside from a few artistic drawings. The outer lining edge of the ceiling was filled with plenty of wasp nests, most having been made vacant some time ago. A number of wasp skins and fragments were littered around the entrance of some of the nest chambers.

The only intact orange spider wasp at the time I entered, was located in the top centre front of the CDBOP. Aside from the occasional movement, possibly as it worked on some home renovations, it didn't appear to me as a threat. Or perhaps it was vice versa with it occasionally pausing, as if to watch me, before continuing on doing its wasp thing.


Upon looking at the photo (#19), I have to question myself as to whether or not it was actually alive. Its thorax (front part) seems to be completely separated from its abdomen (rear part)!

Aside from an occasional gust of wind, single engine planes flying past to throw people out and the sound of small waves crashing in the near distance, the silence was incredible. It amplified the historic importance of the tower, particularly with very few people around and the lack of restorations that are common to tourist attractions. Hence why I avoid visiting places with others.


This awesome experience certainly felt rare, as I stood around taking it all in or occasionally shooting something. After some time, the heat was becoming intense, what with the metal shutters on the southern side bolted closed. As I stepped out of the doorway, a refreshing cool breeze made itself known until I reached the bottom of the stairs and whatever degrees we were up to on that 34 degree day, replaced all sense of refreshing thoughts.


  • The Coast Defences of Western Australia 1826-1963: A Study by R. K. Glyde for personal use (Printed 1991).

bottom of page