Tessarakonteres

The tessarakonteres (τεσσαρακοντήρης, "forty-rowed"), or simply "forty" was a very large galley built in the Hellenistic period. The name "forty" refers to the number of rowers on each column of oars that propelled it. It was the largest ship constructed in Antiquity, and possibly the largest human-powered vessel ever built.

Number of rows of oars
The trireme was the main Greek warship up to and into the Hellenistic period (i.e., at the beginning of the 4th century BC), during which several new galley types were introduced, such as tetrēreis (i.e., "fours", sing. tetrērēs) and pentēreis (i.e., "fives", sing. pentērēs). This led up to the mid-4th century BC innovations of "sixes", "sevens" and so on, even up to "thirteens" and, by the 3rd century BC, a "sixteen". This trend culminated with the tessarakonteres. Little evidence survives about all these ships, and their names have proved difficult to interpret.

During this period ships were increasingly designed as artillery platforms, with enclosed sides and a complete deck. The additional weight all this involved was probably the design imperative for adding extra rowing capacity.

Ships of this type were depicted with up to three banks of oars, so that they were really just larger versions of the bireme and trireme with more than one rower per oar. From galleys used more recently, in the 17th and 18th centuries AD, it is known that the maximum number of men that can operate a single oar efficiently is eight. A "sixteen" is one of the large galleys most frequently mentioned. This could have had two banks of oars on each side, with each oar operated by eight men. However, this theory still leaves the problem of the "forty" without a satisfactory explanation.

Construction
A hull of such size would involve great bend-induced stresses, which were dealt with using strake edge jointing. The plank shear issue was more directly addressed in the ancient practice of mortise and tenon-jointed planks (strakes), which "certainly goes back to 14th century BC and very probably before that".

The average trireme was well short of this scale, intended as it was to be fast in the water and light enough to be hauled up on the beach by the crew. The large scale of the ship's rams that could be cast in the ancient world was determined from a monument that once displayed them.

Specifications
According to an estimation by Lionel Casson, Ptolemy's forty was an oversize catamaran galley, measuring 128 m (420 ft). The twin hull arrangement with a central working platform was designed for stability in sea battles with catapults and could carry 3,000-4,000 marines.


 * Length: 280 Greek cubits (128 m, 425 ft)
 * Beam: 17.5 m (58 ft )
 * Height from tip of sternpost to waterline: 24 m (80 ft)
 * Length of steering oars: 13.5 m (45 ft 6 in)
 * Longest rowing oars used: 18 m (57 ft 8 in)
 * Oarsmen: 4,000
 * Marines: 2,850

Record-holder
The Guinness Book of Records recognizes it as the world's Largest Human Powered Vessel.