The bireme is a type of ancient ship which was supposedly invented by the Phoenicians and extensively used by the Romans. A bireme is also basically a Greek ship which has two sets of oars on each of its sides. In the name bireme, “bi" stands for two and “reme" stands for oars. Strong and beautiful sailing ships, biremes were used extensively for both naval wars and transportation purposes.
Image Credits : Bireme model at Britannica (https://media-2.web.britannica.com/eb-media/90/13690-050-AB9D3871.jpg )
The usage of bireme dates back to 250-400 BC when they were used for the first time as warships. Biremes at that time measured only a few meters in length but were tough and powerful. The salient feature of bireme, whether big of small, was the large square sail, which helped in its propulsion. Bireme was also used extensively by the Greeks during the famous Trojan War.
Technically, both Bireme and Trireme evolved from a type of ship known as the unireme. Unireme, as the name suggests, had only one row of oars located on either sides of the ship. The design and construction of these boats were similar to that of the Bireme and Trireme, but were smaller in size and a bit heavier as well. Unireme even had small rams known as the embolon attached to its keel.
Bireme Constructional Details
Biremes were basically war ships with broad bottoms and shallow draft. Two sets of oars on either side of the ship was the main mode of propulsion, though the huge square sail also assisted in the same. The number of oars per ship ranged between 30-50, each measuring up to 4-6 meter in length.
Biremes were made with outriggers that allowed them to have two rows of oarsmen one above the other. The design was such that the upper row was more outside than the lower row, which allowed the oarsmen to row without interference from the oars of fellow oarsmen. The positions of oarsmen, one top of the other, were also designed in an alternate manner so as to avoid any kind of hindrance. The fulcrums of the oars were fixed to the rails of the ship and helped in a smooth rowing process. Some of the biremes had as many as a hundred oarsmen arranged on a single ship. The oarsmen were given special training to row in a synchronized manner on the ship.
Later on biremes were modified to make triremes, which was a kind of upgraded version, much lighter in weight and having less cargo carrying capacity. Both biremes and triremes were oar-powered ships. However, the trireme was known for its extraordinary speed. They also had a narrow hull and an outrigger which was wider than that of the biremes. Some of the triremes had great propulsive power, which was a result of around 170 oarsmen arranged in three tiers along the sides of the vessel. Everything about the trireme was light weight. The hull was made thin, and so were the keel and transverse. This enabled triremes to attain a speed of seven knots just with the sail and nine knots along with the oars.
As triremes were made mainly as war ships, their construction included a bronze ram that extended from the keel below the water line. The ram was used to pierce the hulls of enemy warships. Apart from this, triremes also had bowmen and spearmen on board in case they were attacked. Triremes were supposed to be the most advanced ships using naval technology at that time.
Speed and mobility were the forte for triremes and for this reason they were built low to the ground, to ensure that the oarsmen reached the water easily with their oars. The lowest row of oarsmen was just 18 inches above the water line. As a result, many researchers believed that the triremes were not meant for open seas mainly because of their reduced weight. In case they were used for open seas, the rowing port holes were protected with leather bags to prevent sea water from coming inside the ship, especially during rough seas. Moreover, as most of the space on board was occupied by the three rows of oarsmen, triremes had less space for the storage of food and cargo. This was also one of the reasons it was used mainly for shorter voyages.
Image Credits : Trireme at Allempires Website (https://www.allempires.com/forum/forum_posts.asp?TID=15398)