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Naves Oneraria - Freighters |
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General Description The term 'naves oneraria' was a general term meaning "ship of burden" and all were powered by sail. Transport ships were shown in various relief's, mosaics and wall-paintings. They generally had a length to width ratio of about 6:1. They could be contracted to transport military supplies and equipment or even commandeered in case of urgent need. Most were between 50 and 120 ft in length, with a carrying capacity of 60 to 150 tons. However in the Mediterranean, ships of 300 to 500 tons capacity were reasonably common and a few exceeded 1,000 tons capacity. The larger ships usually towed an oared longboat (scaphae) which could have been used tow the mother ship into or out of congested ports, or act as a lifeboat. Two specific wrecks have been identified as roman merchant ships believed to be typical of Northern Europe. One was found in 1910 at London, known as the County Hall ship and dated to the end of the third century. It was of carvel construction with oak planks set edge-to-edge, more than 60 ft in length and with a carrying capacity of about 50 to 100 tons. The second was found near St. Peter Port, Guernsey in the late 1980's and was constructed of thick oak planks fixed to strong frames. It had a flat bottom and single mast well forward. Normal cargo included building materials, metal ingots, wine in amphorae or barrels, olive oil in amphorae, grain and other bulk foods in sacks. Power came from a foresail, single mainsail and topsail. Later a triangular lateen sail became more commonly used to allow the ship to sail closer into the wind. Because they were powered by sail the journey time on any route varied considerably. When sailing with a prevailing wind they could average about 5 knots. But if the winds were unfavourable a journey from Rome to Egypt could take a few months. Therefore cargoes could not be perishable, or if passengers were carried they could not be in a hurry if sailing in the wrong season.
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This page last edited -
20 July, 2012.
Copyright © Ian M King, except where otherwise indicated. |
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