John Francis Coates, OBE (30 March 1922 – 10 July 2010) was a British naval architect best known for his work on the study of construction of the Ancient Greek trireme. His research led to the construction of the first working replicas of triremes, the fastest and most devastating warship of Mediterranean empires, and gave a greater understanding of how they were built and used. He also carried out research into the use of shipping in Northern Europe during the Bronze Age, in particular the Ferriby Bronze Age boat and the Dover Boat.
Coates was born and raised in Swansea, the son of chemists Ada and Joseph Coates, Professor of Chemistry at the University College of Swansea. He was educated at Clifton College and took Engineering Science at The Queen's College, Oxford. He joined the Royal Corps of Naval Constructors and in 1943 saw sea service on the Arctic convoys. After the war, he continued to work in the Admiralty. An early project was the design of new inflatable life jackets and life rafts for which he was appointed OBE in 1955. He was the leading ship design architect for the County-class destroyers. Coates remained in Admiralty service until 1979 when he retired for the post of Chief Naval Architect.
In 1982 he was approached by Professor John Morrison of Wolfson College, Cambridge to assist with research into the design of the trireme. Together they and others founded the Trireme Trust, and created a series of small scale replicas based on historical records and architectural theory. Their work eventually led to the construction of a full-scale replica, the Olympias, by the Greek government in 1987. He also worked on the archaeological remains of Bronze Age seagoing ships in Northern Europe, establishing that vessels of considerable size and architectural sophistication capable of large-scale overseas travel existed in the era of 2030-1680 BC.
Coates' elder brother, chemist Geoffrey Coates Ph.D, died in Laramie, Wyoming, in 2013.
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- Dodd, Christopher (2 August 2010). "John Coates obituary". the Guardian. Retrieved 20 January 2018.