The construction of many early binnacles used nails (mid 1700s), which were later discovered to cause magnetic deviations in compass readings. As the development of the compass and understanding of magnetism progressed greater attention was given to binnacle construction to avoid compass disturbances caused by iron.
With the introduction of iron-clad ships the magnetic deviation observed in compasses became more severe. Methods of compensation by arranging iron or magnetic objects near the binnacle were developed. In 1854 a new type of binnacle was patented by John Gray of Liverpool which directly incorporated adjustable correcting magnets on screws or rack and pinions. This was improved again when Lord Kelvin patented in the 1880s another system of compass and which incorporated two compensating magnets.