He first appears in Royal Navy records in April 1778 as a master mastmaker at Woolwich Dockyard; however, this position infers both an apprenticeship as a ship's carpenter and a period in the dockyards as a standard mastmaker. In September 1778 he was promoted to master boatbuilder at Portsmouth Dockyard.[1]
In February 1779 he moved to Sheerness Dockyard, first as master shipwright then as master caulker. By 1787 he was assistant master shipwright at Portsmouth Dockyard, and in March of that year was appointed master shipwright back at Sheerness Dockyard, thereafter having overall charge of all ships constructed there, and from this point the Royal Navy list the ships built under his charge.[2]
In August 1790 he moved to Woolwich as master shipwright, and in February 1793 he was appointed Surveyor of the Navy, working alongside Sir John Henslow. In June 1806 Henslow retired and from then Rule worked with Henry Peake.[3]