This collection comprises forty-eight objects including complete binnacles and parts such as compasses, covers or bases. Binnacles are principally made of timber and brass because those materials do not affect the compass. However, one florid 19th century binnacle is made of cast iron and later examples from the 20th century have aluminium covers. Two are attached to the Museum's vessels but most have been kept from vessels that have been broken up.
The collection is significant in recording the history of navigation. Binnacles were used to house ships' compass. They kept the compass secure and placed it within sight of a seafarer standing at the ship's wheel. The compass was held on gimbals to keep it horizontal despite the rocking motion of the ship. The collection documents the response of binnacles to changes in ship building materials. Compasses could be distorted by even small amounts of metal on a timber sailing ship. In 1838 Britain's Astronomer Royal, Sir GB Airy, developed a method of neutralising the effects of the ship's magnetism by placing magnets and pieces of unmagnetised iron near the compass. Matthew Flinders (1774-1814) made important discoveries about deviation to ships' compasses and, in recognition of his work, the compensating bars around a magnetic compass are called Flinders' bars. The introduction of ships with iron frames and iron hulls increased the problem. In 1878 William Thomson, Baron Kelvin, redesigned binnacles to greatly improve measures to compensate for magnetic deviation and introduced the iron balls that sit on either side of binnacles from that period. They are named Kelvin's balls in his honour.
A South Australian Maritime Museum collection. Access to collection items held in Museum Stores is by appointment only
Binnacle; Compass; Flinders bar; Kelvin
Compasses (Navigation equipment); Maritime history; Navigation
Mariners compasses; Navigational equipment; Watercraft
Nautical equipment; Navigational instruments; Ships' compasses
South Australian Maritime Museum