John Winspear was primarily a ship repairer, building new vessels only when his repair business was quiet. For most of his career he worked alone, although he formed a partnership with Henry Taylor for a number of years.
Winspear was known for first-class workmanship and he built five wooden sailing ships in total, mostly small vessels, the last one being the schooner Ellis launched in 1858.
Various sources have credited Winspear with building two further vessels, Elizabeth and Saracen, but he was not responsible for the construction but the repair and overhauling. Elizabeth was built in 1813 in Lincolnshire and was recorded as being owned by Winspear in 1841. She suffered major damage in 1838 so it is possible that Winspear carried out repairs at that time. Saracen was built in 1838, also in Lincolnshire and was overhauled and owned by Winspear in 1851. He sold her on the same year.
Winspear was plagued by mental health problems and died in 1874 in the County Asylum. At this time the yard was taken over by Dring and Pattison, only to close permanently in 1876 when it was absorbed by the construction of the North Basin.