Tessarakonteres


Tessarakonteres, or simply "forty" was a very large catamaran galley reportedly built in the Hellenistic period by Ptolemy IV Philopator of Egypt. It was described by a number of ancient sources, including a lost work by Callixenus of Rhodes and surviving texts by Athenaeus and Plutarch. According to these descriptions, supported by modern research by Lionel Casson, the enormous size of the vessel made it impractical and it was built only as a prestige vessel, rather than an effective warship. The name "forty" refers not to the number of oars, but to the number of rowers on each column of oars that propelled it, and at the size described it would have been the largest ship constructed in antiquity, and probably the largest human-powered vessel ever built.

Configuration of the oars

The trireme, a three-ranked galley with one man per oar, was the main Hellenistic warship up to and into the 4th century BC. At that time, a requirement for heavier ships led to the development of "polyremes" meaning "many oars", applied to "fours" or more and "fives" and later up to "tens", the largest that seems to have been used in battle. Larger polyremes were built, with Ptolemy II Philadelphus eventually building a "twenty" and a "thirty", and Ptolemy IV Philopator building the "forty".
The maximum practical number of oar ranks a ship could have logistically was three. Beyond three, the number in the type name did not refer to the number of ranks of oars any more, but to the number of rowers per vertical section, with several men on each oar. Indeed, just because a ship was designated with a larger type number did not mean it necessarily had or operated all three possible ranks: the quadrireme may have been a simple evolution of a standard trireme, but with two rowers on the top oar; it may also have been a bireme with two men on each oar; or it may just have had a single rank with four men on a each single oar. Classes of ship could differ in their configuration between regions and over time, but in no case did a "four" ship have four horizontal ranks of oars.
From galleys used in the 16th to 18th centuries AD, it is known that the maximum number of men that can operate a single oar efficiently is eight. Further, Casson writes that the oars were the proper length for no more than eight rowers.
Mention by Callixenus of the "forty's" thranite oars leads Casson to determine that the "forty" had three ranks. He points to the practical limit of eight rowers to an oar, giving a maximum size class of "twenty-four", as well as to the need for a vastly larger deck than one ship could provide in order to accommodate the reported numbers of marines. Combined with Callixenus description of the ship having two heads and two sterns, Casson suggests that the "forty" must have been a catamaran made up of two three-ranked "twenties" joined together by a deck. Each column or section of the ship would be composed of twenty rowers; perhaps eight rowers on each section's top rank, seven in the middle, and five on the bottom rank.

Specifications

As a catamaran of two "twentys" with 4,000 oarsmen, there would be 2,000 per hull and therefore 1,000 per side. The 130m length would allow ample room for the 50 vertical sections of three oars each, with each vertical section accommodating 20 rowers. Thus there would be 150 oars per side. Casson has suggested that it was possible that the two internal sides were not equipped with oars and that the rowers there acted as reserve crew for those on the outer side, so the "forty" would have had either 300 or 600 oars.

Details

Source:
It had seven naval rams, with one primary, and the deck would have provided a stable platform for catapults that were often mounted on supergalleys. However, the "forty" was likely just a showpiece; Plutarch describes the ship as for exhibition only.

Launch

In order to launch the huge ship the engineers devised a – then novel – dry dock construction:
It has been calculated that the dock might have needed around 750,000 gallons of water to lift up the vessel.