nautical technology 157
Roman period and later. The building process was prolonged and expensive: it
required a highly- professional shipwright’s crew and much building material (Pomey
et al., 2012: 392–395; figs 90, 94, 95). The strength of the hull relied on its shell
of planks that made it more durable and robust and enabled the vessel to undertake
long-range shipments of metal, oil, wine and stone artifacts, all on the same voyage.
Furthermore, the hull was sheathed with lead to hold the coating of waterproof
material in place. However, this technology was not common: alongside wrecks
with sheathings there survive others without, and no lead sheathing is reported on
wrecks from later than 200 ce (Arnaud, 2011).
Such strong hulls could accommodate elaborate types of ram. From its first appear-
ance in 900 bce until 680 the Phoenician ram was pointed and could drive a hole
into an adversary’s hull. From the late seventh through the fifth century bce the ram
became blunt, delivering a pounding blow, and from the late fifth century bce, it
evolved into the three-finned ram. Both the blunt ram and the three-finned aimed to
strike the most vulnerable section of a hull, preferably in the sides or stern, to open up
meters-long seams from the point of impact, resulting in unstoppable flooding. The
difference between the two rams lay in the force of the strike, most effective when the
integrity of the hull relied only on mortise-and-tenon joinery: the three-finned ram
concentrated enormous force into a very small area. However, during the pax romana
of the first century ce, there was a return to the blunt ram, which became a distin-
guishing mark of a warship (Pryor and Jeffreys, 2006: 145–146).
Hellenistic shipping, dominant during the early Roman Republic, was gradually
replaced by the Roman, which reached its peak in the first century ce, when the
Mediterranean turned into mare nostrum. Until the empire split four centuries later,
imperial Rome was the greatest maritime power of antiquity. Until the Late Roman
Period, 300 ce, wrecks attest to the use of various sizes according to cargoes and
range of sailing. For local and regional shipping there were coastal vessels of modest
tonnage (2.5–10 tons). For farther destinations the average size was fifty tons. To this
assemblage belongs a short-lived group of 10 wrecks discovered in the western
Mediterranean, categorized as dolia after the large globular jars, presumably placed in
the hold as the ship was being built, intended for bulk transport. Although built in the
shell-first tradition, these medium-size flat-bottomed vessels display innovations
responding to changes in the production and transportation of wine brought about
by Roman expansion. The relatively short period of production for this ship-type may
have been due to problems in design and the gradual replacement from this period in
the western Mediterranean of amphoras by barrels, thus economizing on shipping
and handling costs for a given volume of liquid (Heslin, 2011). Also notable, how-
ever, are those ships, far larger than in previous periods (of 200–300 tons) carrying
amphoras and building materials, or obelisks (200–500 tons), and the occasional
vessels of 1000–1200 tons for transporting grain from Egypt to Rome (Wilson, 2011:
39–40).
Several innovations in nautical technology from the Republican period underlie
the relationship between ship architecture and environmental constraints. The first
regards rigging. Under the Late Republic and Early Empire, it became standard for
merchant ships to carry two square-rigged masts, the main central one and a foresail.
As evidenced by iconography and shipwrecks, there are two types of bowsprit sail that
attest to two types of sailing, upwind or before the wind. One bears a sprit-yard and a