The construction of the ship began with the construction of the hull plating from boards, usually pine. Then a light skeleton was placed inside and the whole structure was reinforced with thick ropes. Boards were connected with specially hewn pins or grooves, practically no nails or other metal fasteners were used.
In this way, a smooth hull was obtained that did not resist water. It was only then that frames were inserted, after which the sides of the ship were reinforced with thick hardwood bales, for example oak. In addition, at the front, at the waterline level, was placed a strong ram wrapped in iron, copper, bronze or bronze. Wooden sides reinforced with metal usually protruded from both sides of the ship. Their task was to protect against enemy rams and to break enemy oars. In addition, anchors were hung on them. The height of the sides depended on the type of ship, usually from 140 to 180 centimeters. Above them, the ship’s deck protruded, usually not exceeding 2.5 meters above sea level. Warships were never built of freshly cut boards because of their excessive humidity. To get rid of it, the wooden elements of the structure were dried in the open air. When launching the ship thus made, the wood swelled, which further strengthened and sealed the whole structure. For battle purposes, huge eyes were painted next to the bow. In this way, the front of the ship could cause fear to the enemy because of its “animal” appearance.
The most commonly used watercraft at that time was the galley (the name comes from the fish of the swordfish species (galeos), having an elongated shape), i.e. a sailing vessel equipped with oars (navis oneraria). At the turn of the 4th and 3rd century BCE, when the Romans did not carry out significant operations at sea, and since there was no strictly war fleet at that time, the role of battle ships was performed by larger cargo ships or smaller merchant units, which were rearmed and directed to specific actions. armed.
During the republic, the most commonly built types of ships in Roman shipyards were: triers (trireme) and pentery (quinquereme). The Roman tri-row (triremis) was (depending on estimates) 35 to 40 meters long, 4 to 6 meters wide, and its draft was from 1 to 1, 5 meters. There were usually 174 rowers, 30 sailors and 40 to 120 soldiers on board, depending on the threat of a direct sea attack. The second type of ship used by the Romans, the five-row (quinqueremis), was about 42 to 50 meters long, 6 to 7 meters wide, and draft up to 3 meters. Its displacement was about 530 tons, while the crew consisted of 300 rowers, 47 sailors and from about 50 to 130 soldiers.
The Romans also built larger vessels, for example deco ships (deceres) – ships with enormous tonnage for the realities of the day, able to take on board a crew of 572 rowers, 30 sailors and 250 soldiers, plus 2 battle towers and 6 ballista or smaller catapults. Their length was from 40 to 45 meters in length, while the draft was 2 meters. For reconnaissance operations, auxiliary ships equipped with one row of oars (e.g. lembi, veloces and celeres) or double-breasted biremy (biremis) were built. In the case of combat operations, they joined the direct fight or had supply functions. Polybius wrote about the tasks of this type of unit, discussing the Roman-Macedonian Second War:
During the winter Philip took into consideration that for his enterprise he would require ships and crews to man them, not it is true with the idea of fighting at sea — for he never thought he would be capable of offering battle to the Roman fleet — but to transport his troops, land where he wished, and take the enemy by surprise. Therefore, as he thought the Illyrian shipwrights were the best, he decided to build a hundred galleys, being almost the first king of Macedonia who had taken such a step.
The speed of Roman ships is defined at 3 to 9 knots (1 sea knot=1.85 km / h), with the lower limit referring to the usual rowing speed, and the upper limit to the fastest one used during battles. Due to the enormous effort of the rowers, it was possible to swim no more than 20 minutes at maximum speed. There was also an intermediate pace, the so-called accelerated one. It was about 5 knots and its holding time extended up to 3 hours.
To determine the number of nautical miles traveled, a structure consisting of discs and gears had to be mounted on board. The mechanism of its operation was described by Vitruvius:
Thus, when the vessel is on its way, whether impelled by oars or by the wind, the paddles of the wheels, driving back the water which comes against them with violence, cause the wheels to revolve, whereby the axle is also turned round, and consequently with it the drum-wheel, whose tooth, in every revolution, acts on the tooth in the second wheel, and produces moderate revolutions thereof. Wherefore, when the wheels are carried round by the paddles four hundred times, the horizontal wheel will only have made one revolution, by the striking of that tooth on the side of the vertical wheel, and thus, in the turning caused by the horizontal wheel every time it brings a ball to the hole it falls through the channel. In this way, by sound and number, the number of miles navigated will be ascertained. It appears to me, that I completed the description in such a manner that it will be easy to comprehend the structure of the machine, which will afford both utility and amusement in times of peace and safety.
Ships in the service of the Republic usually had their own names. They usually came from the names of gods, heroes or concepts symbolizing values particularly valued by the Romans, among which “victory” (victoria) predominated.