Caithness Field Club 

Caithness Field Club Bulletin 1993

SHIPS V BROCHS

There are between 500 and 2000 brochs north of the Caledonian canal built around 100 BC. Richard Hingly proposes that they were built for status rather than defence, like the later tower houses.  I feel that the approximate uniformity of the broch design implies a central control and a serious external threat, a threat serious enough to impel the local chiefs to accept that central control. (The Cold War provides many such examples in our own time.) The progressive development of brochs, for example the provision of a ledge to support a first floor, suggests that the threat persisted for decades.

As the brochs are distributed near arable land around the coast, the threat is presumably from the sea, and the defences would suggest protection against an invading force of at least a few dozen men.  These invaders must have started their journey outside the broch-defended area so must have travelled over 100 miles in one or more substantial craft. The broch builders travelled to Shetland so must have used boats themselves, but built fortifications also, as the Greeks and Romans were doing.

On the Mediterranean by 300 BC the classic trireme with three banks of oars was well established, 40 m long, rowed by 170 men, but such craft were fragile. More robust were the corbita, 86 ton cargo merchant ships with a main mast and a bow-sprit foresail. During Hannibal's campaign in Italy in 210 BC he renewed his force of elephants by importing more by sea, so his ships were large.

By 56 BC Julius Caesar described the 220 sailing ships of the Veneti, the ferry boats of the channel coast, as having cross timbers a foot wide, fastened by iron bolts as thick as a man's thumb, and anchors secured by iron chains instead of ropes.  The sails were made of leather. The hulls were too solid to ram and too tall to board with grappling irons.  The ships could be run aground safely, even on a rough beach. The Romans finally defeated them by cutting the halliards which brought down the mainsail. The Veneti only sailed on the Channel, but it is probable that similar craft worked the coasts of the North sea, and may have descended from the ships which threatened the brochs.

Published in 1993 Bulletin