Secrets of bigger, faster medieval ships are uncovered by Channel Island ferries

The most complete collection of medieval shipwrecks found in British waters has been discovered by archaeologists off the Channel Islands, with the remains of at least three vessels located so far and more discoveries expected in the near future.

The most complete collection of medieval shipwrecks found in British waters has been discovered by archaeologists off the Channel Islands, with the remains of at least three vessels located so far and more discoveries expected in the near future.

One of the vessels almost certainly dates from the second half of the 13th century, while a second is from the late 14th or early to mid-15th century.

The vessels - each one estimated to be up to 30 metres long - are lying buried in mud about 300 metres outside the old harbour at St Peter Port in Guernsey. One of the vessels is believed to be more than 50 per cent complete. So far, eight large sections of hull have been found from three ships.

The excavation project, which has been jointly organised by Guernsey Museum and the maritime transport company Commodore, and led by Dr Jon Adams, a marine archaeologist at the Universityof Southampton, is also examining evidence of what the ships' cargoes may have been.

Up to now, the finds suggest that the merchants were transporting cargoes of wine and pottery. The remains of more than 100 pots made near Bordeaux during the 13th century, with fragments of wine barrels, indicate that the oldest of the three vessels was carrying wine and ceramics from south-west France, which was then ruled by England, to Guernsey, and perhaps England.

It is likely that the vessel from the late 14th or 15th century was heading from southern Portugal with a cargo that included ceramic flasks and bottles for holding and serving olive oil.

The ships may have come to grief because of two dangerous reefs that once existed outside St Peter Port's old harbour. These rocks were removed during the 18th and 19th centuries. Before that time, all vessels calling at the port had to steer accurately between these hazardous rocks; the port's extraordinary 10-metre tidal range would have made navigation even more difficult, and the archaeological evidence suggests that many ships' captains got it wrong.

The St Peter Port wrecks have come to light through seabed erosion caused by large modern vessels. As ships' draughts have grown and propeller sizes have increased, stronger currents have removed mud and sand from the seabed and exposed these ancient timbers.

The find is likely to be of international importance. Remnants of medieval ships are rare: the only comparable craft excavated in the past have been found in the Baltic Sea.

Dr Adams said: "This discovery suggests that more ships of larger size were being built earlier than we suspected. It shows that the medieval shipping industry was advancing faster than we had thought, and it provides a valuable insight as to how these medieval increases in ship-size made it possible for subsequent technological changes... which allowed European states to launch the age of exploration in the late 15th century."