The Roman navy was the most economical and fastest means of supplying the army in Scotland. A merchant ship carrying 1 ton of food could go 1280 miles whereas a mule could take the same weight 2.4 miles for the same cost. The Romans set up a series of ports that allowed large amounts of cargo to be transported from Britain, Italy and further afield. These cargoes were unloaded at local ports and then taken by smaller craft to British ports. For inland forts on rivers barges (codicaria) were then pulled upriver by men to supply forts. As an example, one man could pull 50 tonnes in weight on a barge. Other vessels such as oar driven myoparo and scapha could also be used. Forts along the Antonine Wall would be supplied from the ports by the extensive road system.
The standard Roman military boat of Classis Britannica, the name of the Roman navy in Britain, was the liburnae bireme with its flax sails and two rows of oarsmen. The oarsmen were never slaves and were highly trained at special schools called icria with mock-ups of oar systems to allow manoeuvre practice. The oarsmen were militia who then fought on land. The militia on these ships wore chain mail with conical helmets and round leather and wood shields.
Biremes, triremes were named according to the number of banks of oars. Bigger and bigger classes of Roman navy ships appeared – quadriremes, quinqueremes and so on. The most common type of ship was a liburnae bireme 30m long holding up to 200 men. Oarsmen would power this craft and shields would be carried above the oar ports. The bows of these ships would be brightly painted. Each Bireme was named in a similar fashion to modern ships.
The Roman Navy circumnavigated Scotland and Ptolemy produced a map that showed the “Orcades” if slightly skewed in their orientation.