During a career that began in the 1950s, she led many excavations in the Mediterranean and was noted for her skills as an illustrator and her work on the technicalities of ancient boat-building and nautical equipment, particularly the use of stone anchors and their typology.
Among her most important projects was an expedition, sponsored by Unesco, which she led to survey the Pharos (lighthouse) site in the Port of Alexandria in 1968. She dived the site and confirmed the existence of ruins representing part of the Pharos as well as the remains of submerged buildings representing the lost palace of Alexander and the Ptolemies, and published a preliminary report with drawings which revealed the site’s importance.
For the next two decades, however, the site remained more or less forgotten, because of a lack of specialised archaeologists and the fact that the area was in a military zone. It was only in the 1990s that work there resumed.
In 1971 the Sicilian authorities and the British School at Rome appointed Honor Frost to direct the excavation of a Punic warship in Marsala harbour off the coast of Sicily. It is believed to have been one of the Liburnian “longships”, an oared vessel with 17 sweeps per side, used by ancient Carthage in the Battle of the Aegates Islands (241BC), the last battle of the First Punic War between Carthage and the Roman Republic.
The ship had been uncovered by a dredger in 1969, and for several years Honor Frost and an international team of marine archaeologists worked on the site, publishing regular reports, before eventually restoring the wreck for display at the local museum.
She concluded that the warship had sunk stern-first after being rammed by the Romans. The crew had apparently abandoned ship, taking their weapons with them, but left evidence of their diet, including deer, goat, horse, ox, pig and sheep as well as olives, nuts and fruit. There were also traces of cannabis, which the crew may have chewed as a stimulant before going into battle. The team also found a human skeleton, possibly of a Carthaginian sailor trapped by ballast. The ship’s “nationality” was painted on the sides with letters by its Punic builders.
An only child, Honor Frost was born on October 28 1917 in Nicosia, Cyprus. After the death of both her parents she became the ward of a London solicitor, Wilfred Evill.
She studied at the Central School of Art, London, and the Ruskin School of Art, Oxford, then worked as a designer for the Ballet Rambert, and later as director of publications at the Tate Gallery.
Honor Frost was, as she put it, “baptised” into the delights of underwater exploration in a garden well in Wimbledon. She had been invited to try a diving suit attached to a hand pump which had been used in the Second World War for shallow water work and, as she descended, found herself entranced by the beauty of her surroundings: “air bubbles, like quicksilver, adhered to undercut surfaces. The floor was a cushion of dead leaves in every stage of decomposition.” Underwater, she found, “the mind loses its habits of anxiety, while powers of contemplation increase”.
She soon became convinced that “time spent on the surface was time wasted”, and, in the late 1940s, began training at Cannes with the Club Alpin Sous-Marin.
It was with the club, under the guidance of the archaeologist Frederic Dumas, that she dived her first wreck, a large Roman ship lying at the foot of a rock called the Balise de la Chretienne off the south coast of France at Antheor. “Around 15 metres I could just make out the wreck, or rather a tumble of amphorae extending as far as the eye could see,” she recalled. The wreck was inhabited by a colony of octopuses, “graceful, playful and as sensuous as cats when tickled”.
In 1957 she reported for work for the last of six seasons of an excavation, led by the British archaeologist Kathleen Kenyon, of tombs near Jericho. Though she did not enjoy working on dry land, Honor Frost was struck by the contrast between the gung-ho excavation of the Roman ship and the discipline and careful record-keeping of land-based archaeology, particularly the way in which the “context” of the tombs was studied in as much detail as their contents.
The experience convinced her of the importance not only of recording shipwrecks of particular historical interest photographically, but also of representing them in meticulously detailed plans and finding out as much as possible about the surrounding sediments.
After the Jericho dig was over, Honor Frost moved to Lebanon, where she explored the ancient harbours at Tyre and Sidon and along the Syrian coast. She developed an interest in stone anchors after spotting several built into the walls of the bronze age temple at Byblos, and then discovering similar anchors off the nearby coast.
Among other achievements, Honor Frost was the first to recognise, in 1959, that a wrecked ship off the coast of Turkey at Gelidonya, which contained a rich cargo of copper and tin ingots together with personal possessions of the crew, dated from the late Bronze Age and was early Phoenician. At the time of the discovery, scholars believed the Myceneans had dominated Mediterranean trade in the Bronze Age and that the Phoenicians were not present on the seas until the Iron Age.
From her guardian, Honor Frost inherited a valuable collection of art and antiques and a Georgian house in London, where she entertained an eclectic circle of friends, including Erica Brausen, director of the Hanover Gallery during its heyday, and the fashion designer Thea Porter. Her fascination with the Mediterranean eventually led her to acquire a house in Malta as a second home.
Among other works she wrote Under the Mediterranean (1963), about her early experiences as an archaeologist. She was also a frequent contributor to the Mariner’s Mirror, the journal of the Society for Nautical Research.
Honor Frost was elected a fellow of the Society of Antiquaries in 1969. In 1997 the French government awarded her a medal for pioneering submarine archaeology in Egypt, and in 2005 the British Sub-Aqua Club presented her with the Colin McLeod award for furthering international co-operation in diving.
Two hip replacements in later life did little to slow her down. Shortly before she died, on September 12, she was planning another season at Sidon and a trip to India to see what she believed to be the largest stone anchor in the world.
Honor Frost was married but separated.