A version of the bireme with an obtuse prow which could be used either used as a very fast merchant ship or as a warship was produced in Samos during the period of Polycrates. 520-500BC) The name of the first ship of this type was Samaina. Modification to the traditional bireme hull design involved increasing the beam in order to enlarge the space for cargo. The "Samainae” had a continuous deck which was different from other ships. There two types of Samaina: the first had 25 oars in each side (Pedikodoros) and the other allocated 25 x 2 rows oars per side (double Pedikodoro).
The linesplans of Samaina are shown below They refer to boat length 25.33 m, maximum width 2.76 m and a height of 2.42 m in the middle. (Length to width ratio of 6:1).
Samaina was a little longer, than Argo more beamy and has a raised and extended foredeck, But she still did not offer much more space for cargo or passenger accommodation on facilities than does Argo.
The Samaina’s lines-plan reveals that its bow had a more bulbous ram profile at and below the waterlines than was the case for conventional biremes and triremes. Its function was not primarily intended for warfare (ramming opponents) but rather to improve hull performance in the water by producing a super-cavitation effect underwater around the hull.
This bow principle, innovated in Samina, has also been proved in modern hull design. For example, In 1992 British Waterways and Alvechurch Narrow Boats, UK, produced a new hull design for narrow boats which was said to produce less bow wave, less wash, less damaging water pressure on the fish and voles, better steering in both directions and which required less power. A 1.5 litre engine, instead of 2 litres, was sufficient to power a 21m narrow boat with this bow profile.