The ketch was developed in England and North America during the 17th century as a small coastal trading vessel with a capacity of about 50 tons. Whilst the sails were essentially the same pattern as the brigantine – two masts, square-rigged on the fore and gaff-rigged with square-rigged topsails on the aft – there was a notable difference in that the fore-mast, which was set further aft than on most two masted vessels of the day, was the taller of the two.
The type had a career during the eighteenth and early nineteenth centuries as bomb vessels – the relatively uncluttered space between bow and foremast used to set up one or two mortars or howitzers to lob explosives into shore fortifications. Extensions to this space gave the craft more speed and stability and the extra reinforcement to the bow area designed to take the recoil of the weapons, gave the vessel another use - Arctic exploration.
After the development of exploding shells and revolving gun turrets made its war use obsolete it reverted to coastal trade and mail delivery and, during the course of the late nineteenth century, the rigging became all fore-and–aft.
Many ketch-rigged yachts of today use Bermudian-rig instead of gaff-rig on the mizzen mast.
- A nineteenth century working ketch, the "May Queen", is semi-permanently moored at Constitution Dock in Hobart, Tasmania as part of the Tasmanian Maritime Museum. The photographs on the link below show a ketch in full flight.
- Terms in Bold - see Sailing ship types: Glossary