thumb|320px|Sectional drawing of well smack
A well smack was a type of traditional fishing boat in use in the United Kingdom and then the Faroe Islands between the late 18th century and around 1920. It had a well amidships. The well was filled with circulated external water, which kept fish alive until delivered to land and sold. It was a modified form of a fishing smack.
History
Between roughly 1775 and 1875, "well smack" referred to a 50-foot gaff cutter used in long-lining for cod, ling, turbot, and other bottom-living sea fish. These vessels were also known as cod boats. From roughly 1875 to 1920, they were extended to make 80-foot gaff ketches, sometimes by the cut-and-shut procedure. Some were built as new 80-foot welled smacks; some were turned into dry ships for use with ice.
Structure and usage
thumb|left|[[Gaff rig|Gaff cutter rig]]
These smacks were heavy-hulled with a draught of two fathoms. They were buoyant fore and aft, with the well contained amidships. Auger holes were drilled in the sides of the hull so that water could flow freely for re-oxygenation. Fish placed in the well could then be carried upriver to market (from 1750 especially Billingsgate, London; from 1900 the Faroes) in fresh condition.
By about 1854, the Thames was too polluted for use of welled smacks, and fishermen had to leave fish in floating cod boxes in the Thames estuary near Ipswich. Many fishermen moved out of Thames fishing ports such as Barking, and went to the east coast, especially to Grimsby and Lowestoft. Some cod boats, including some welled smacks, did continue to fish out of Barking until around 1900. However most continued to carry the Port of London port-registration LO.