Commonwealth lightship CARPENTARIA (CLS4)

Maker Commonwealth Naval Dockyard, Cockatoo Island (Australian, 1913 - 1935)

Date1917

Object number00000085

NameLightship

MediumVarious materials

DimensionsVessel Dimensions: 21.94 m × 21.5 m × 7.82 m × 2.74 m, 164 tonnes (71.99 ft × 70.54 ft × 25.66 ft × 8.99 ft, 161.38 tons)

ClassificationsVessels and fittings

Credit LineANMM Collection Transfer from Department of Transport and Communications

DescriptionCommonwealth Lightship 4 (CLS4), CARPENTARIA, was one of four uncrewed lightships designed by D & C Stevenson of Edinburgh and built at Cockatoo Island Dockyard, Sydney in 1916-17. It originally used an automatic acetylene light with a sunlight-operated valve to turn it on and off. Painted red with its name in huge letters on the side, it was easily recognisable to navigators. CLS4 retired in 1985 after an encounter with container shipping in Bass Strait almost sank the vessel.
HistoryLightships are floating lighthouses placed where a permanent light is impossible to build, to warn ships of hazards and to act as navigational aids. Shoals and shifting sandbanks which often lie out to sea and may be submerged at high tide present a very real danger to shipping. Outcropping rocks that defy the construction of a lighthouse on them can only be marked by floating lightships or buoys.

A lightship usually has no propulsion of its own and is taken under tow to its position at sea. The machinery space is used for equipment to run the powerful light for months at a time. Lightships are given distinctive features to make them easily recognisable during daylight hours. By night each lightship has its own code of light flashes.

As part of the Commonwealth’s responsibility for the safety of navigation at sea, four lightships were built at Cockatoo Island Dockyard, Sydney, in 1917–18. Named Commonwealth Lightships (CLS) 1 to 4, they were built to the design of D & C Stevenson, naval architects of Scotland. One was moored at the Merkara Shoals in the Gulf of Carpentaria and another anchored on Breaksea Spit north of Sandy Cape, Queensland. The others were kept in reserve. The light on CLS4 was powered by a six-month supply of acetylene gas held in tanks. The flow of gas, which was ignited by a pilot flame, was controlled by an automatic mechanism to produce the characteristic code of flashes. A warning bell tolled with the rolling of the ship.
SignificanceThis lightship represents the different methods required for ensuring safe passage through waterways where permanent fixtures were not possible.