Document ID: chunk:federal_register_of_legislation:F2014L00095:body:0:p12
Version: federal_register_of_legislation:F2014L00095
Segment Type: other
Provision Reference: 
Character Range: 29994–32493

together with joints reinforced with wrought iron straps and brackets. The walls were lightly braced by timber braces, which would have served to stabilise the timber structure before the iron shell was fitted. At Dent Island there was just one intermediate floor with hardwood joists and pine floorboards. In the centre of the tower was a vertical timber weight tube, which formed a central support for a winding timber stair that ran part of the way up the tower. On the upper level, where the conical tower was too small to fit a stair, there was a fixed ladder up to the level of the light room and balcony.

The tower frame was supported at the bottom by a segmented cast iron ring that formed a base, bolted to a massive concrete footing and floor cast within a low stone wall. The timber posts were bolted to lugs made as part of the iron base ring. At Dent Island, because the tower was quite short, a pit was formed in the middle of the floor to provide a longer drop for the weights that powered the clockwork that rotated the lens.

The tower was clad with a covering of wrought iron plates, about 3 mm thick, which were rolled to conform to the conical shape. The plates were lapped and riveted, and screwed to the timber framework and to the iron ring at the base. A timber door was fitted at the bottom of the tower, and glazed windows at each floor level.

At the top of the tower was a timber-framed structure, which formed the floor of the lantern room, and the projecting balcony that surrounded the lantern room. This balcony had a flooring of timber boards with a waterproof covering of lead sheet.

The lantern (the structure which enclosed the lantern room, and which protected the optical apparatus) had three main parts — the base, the glazed section and the roof. The base (sometimes called the murette) was round in plan, framed in timber, clad with iron on the outside and with timber boarding inside, and capped with an iron sill. There was a low door in the base through which the keeper could crawl out onto the balcony. Above the base was the glazed section, with flat trapezoidal glass panes in a slender framework of iron. On top was the lantern roof (sometimes called a dome or cupola) of galvanised iron sheeting on an iron frame, curved to form a hemispherical dome. At the peak of the roof was a weatherproof vent for the lamp smoke to escape. All of these parts were locally designed and made in Queensland.

The optical apparatus was mounted inside the lantern