One of the variant of Greek bireme is depicted on the picture. These narrow and fast vessels were built without frames on outer templates with strengthening of their planking by treenails, which were used in construction of Egyptian vessels, but only with difference that Greeks used round treenails the both ends of which were cut. In such a cut small wooden wedges were hammered made of acacia, plum tree or sloe. Then treenails were fitted in such a manner that wedges were spread across the fibre. So the planking boards were fitted closely to each other. The ram was usually strengthened to the keel beam and was made in the form of a trident or a wild-boar head. The stem at the upper part of the ram had a chock in which a strong rope was entered to join several ships at close order attack. The depicted bireme had a lattice bulwark and the oars of upper row of rowers were supported by outer-board bearings. The oars of the lower row of rowers were put into the board holes. Leather covers defended the holes and prevented water penetration inside the ship. The crinoline went along the board of a ship with its flooring laying on long beams. Free ends of beams were supported by sloping bearings. This type of ships was often equipped by an additional row of oars and was used as a trireme.