A compass gimbal from Mermaid

Written by Carl Tanner, compiled by Dr Madeline Fowler

The final part of a blog series written by undergraduate students at James Cook University, who undertook research on objects in the Museum of Tropical Queensland’s maritime archaeology collection as part of the 2017 topic AR3008 Boats and Beaches.

The shipwreck

HMCS Mermaid was built at the Howrah Dry Docks on the Hooghly River in Calcutta, India, in 1816, by the shipwrights Thompson (Phipps 1840:108, 123). Built out of Indian teak, it was iron-fastened and clad in copper sheathing along the keel (Hosty 2009:17). Designed as a cutter, it was originally rigged as a one-masted ship, but was refitted later into an armed, two-masted schooner (Hosty 2009:17; ANSD 2017). The ship displaced 83-85 gross registered tons, was 17m in length, 5.48-5.6m in beam and had a draught of 2.7m (Hosty 2009:17; Phipps 1840:123; ANSD 2017).

Bought off the vessel’s builders by the governor of the NSW Colony, Lachlan Macquarie, whilst the vessel was in Port Jackson/Sydney in 1817, the vessel was duly commissioned into the Royal Navy as the cutter HMS Mermaid. Its purpose whilst in service was to act as a survey vessel for the Navy, in its capacity within the British Empire’s far eastern colonies: the colony of NSW and the remainder of the continent of ‘New Holland’, as Australia was known at the time. It came under the command of Lt Phillip Parker King, RN, son of the former governor of NSW, Philip Gidley King. Born in 1791 on Norfolk Island, but raised in England, King was sent to NSW with a commission to survey the uncharted coast of New Holland for the British Government after the end of the Napoleonic Wars. It was deemed that, ‘consequent upon peace, it is most important to explore, with little delay as possible, that part of the coast of New Holland not surveyed or examined by the late Capt. Matthew Flinders (Hosty 2009:17). Between 1817 and 1820, King charted much of the coast of New Holland in Mermaid, of which he wrote much about in his accounts of the voyages. It ran aground in 1820 and was then refloated, limping back to Sydney, heavily damaged (King 1827). In 1823, the vessel was condemned for survey work and pensioned off, to be sold to the NSW colonial government.

Renamed HMCS Mermaid, the vessel was now used by the colonial government for business errands and trade between NSW and various colonies and destinations around the Empire and elsewhere, including New Zealand, India, Timor and to various outposts along the coast of New Holland. It was also used for exploration work. In 1823, under the command of the explorer John Loxley, Mermaid sailed north from Sydney to survey and explore the coast of the colony south of Port Curtis (now Rockhampton, QLD). Loxley discovered the Brisbane and Tweed Rivers during that voyage, as well as rescuing two stranded convicts from the Moreton Bay area, Thomas Pamphlett and John Finnegan, who guided Loxley along the Brisbane River and Moreton Bay. The latter become an explorer himself. In 1825, Mermaid brought the explorer Edmund Lockyer to the Brisbane River, in order to explore the upper reaches of the river for the purposes of founding a new colony. That colony became Brisbane, which subsequently became the capital of the new state of QLD on 6 June 1859 (Brisbane Courier 1869:6)

Unfortunately for Mermaid, its time as a working vessel was drawing rapidly to a close. After a number of other voyages, namely at the behest of the colony at Port Essington on Melville Island in the Northern Territory, Mermaid was on a return voyage along the QLD coast when tragedy struck. Under the command of Capt. Samuel Nolbrow, Mermaid left Sydney on 16 May 1829, bound for Port Raffles, with government dispatches and provision for the colony at King George’s Sound. Early on the morning of 13 June, Mermaid ran aground on an uncharted reef (Nolbrow reported the coordinates as 17º7’S, 146º10’E). The vessel was bilged and all on board survived, only to be rescued four more times on their way to Port Raffles, having run aground another four times on their way to the port (Hosty 2009:17)! They arrived back in Sydney five months later (Hosty 2009:17-18; Australian 1829:3). News of their wreckage and subsequent debacle back to Sydney has been written about in numerous newspaper accounts, for example Albany Advertiser (1935:3), Australian (1829:3), Brisbane Courier (1925:18), Cairns Post (1923:8) and Examiner (1909:4).

The artefact

MA9932 was found on the site of the wreck of HMCS Mermaid and appears to be a corroded, yet mostly intact, metallic ring approx. 230mm in diameter to the outer edge of the ring and 270mm in width across the two ‘lugs’ attached to the ring. It is 22mm high in profile and 5mm in width.

MA9932 a

The surface of the ring is corroded to depth, with small scale pitting and bubbling of the surface evident. The colour of the corrosion ranges from a whitish grey, tawny to dark brown with some black to various shades of green-blue. The predominant colour, though, is green-blue.

MA9932 b

Given that this object was found in saltwater, the corrosion seen would suggest that the object is made out of copper metal, the corrosion of the copper to green-blue being due to a combination of oxidation from dissolved oxygen in the seawater, as well as dissolved salts (NaCl2, Na2OH, etc.) attacking the copper. Some oxidation of the copper metal would lead to various copper oxides forming (CuO, CuO2, etc.), giving the more red/tawny brown patches, whereas copper salts would show as whitish-grey and other colours.

MA9932 g

On opposite sides of the ring, perpendicular to the site of the ‘lugs’, are two holes that appear to be attachment points. One hole has been broken apart, with the bottom of the ring having corroded off. From the size and shape of the ring, the position of the lugs and the two holes, and the metal the ring is made of, although no identifying marks could be traced anywhere on the ring’s surface, it is believed the ring is a support, or gimbal, for a ship’s compass.

MA9932 c

Highly valued pieces of ship’s equipment, the gimbal compass was designed to remain in a horizontal plane, despite the vessel it was on board pitching about, thereby keeping an accurate determination of the ship’s bearing. Usually, the compass and gimbal was built into a metal or wooden casing, with the manufacturer’s stamp on the case. The compass bowl would sit inside the gimbal, attached through the two holes via pins and screws, with the lugs acting as rocker arms, sitting inside another ring assembly or supports. Other than the gimbal, no other pieces of the compass were found.

MA9932 f

 Statement of significance

The importance of the cutter HMCS Mermaid to the annals of Australian maritime, coastal and exploration history cannot be understated. Though only a small vessel and with a relatively short career spanning 13 years, from its launch to its eventual wrecking upon Flora Reef in Far North QLD, Mermaid contributed significantly to opening up of the northern part of Australia. The compass gimbal which was once part of the ship’s equipment, is now also a part of that history and worthy of inclusion within it. MA9932 found at the wreck of HMCS Mermaid not only formed a part of a very important piece of equipment on board the vessel, it is also a part of the ships’ and also of QLD and Australia’s maritime tradition and history. Though it is but one part of the ship, its importance to the ship’s function is a part of the overall story of Mermaid and of how that vessel became a wreck, far from home.

This compass gimbal and other objects from the Queensland Museum’s maritime archaeology collection can be viewed on Collections Online.


ANSD, 2017. Australian National Shipwrecks Database, Australian Government: Dept. of the Environment and Energy, Canberra


Hosty, K. 2009. We find the missing Mermaid. Signals 86:14-20, 30-31.

King, P.P. 1827. Narrative of a Survey of the Intertropical and Western Coasts of Australia, Vol 1 & 2. John Murray: London.

Phipps, J. 1840. A Collection of Papers Relative to Shipbuilding in India. Scott and Co: Calcutta.