IsisLucian gives fairly specific dimensions: the Isis is 120 cubits (180 feet) in length, more than a quarter of that (45 feet) in beam, and 29 cubits (43.5 feet) from the deck to bottom of the hold at its deepest. Based on these figures, Casson has calculated her capacity at 1,200 to 1,300 tons -- a figure not at all improbable given the scale of the Roman grain trade, the skill of Roman shipwrights, and the collateral evidence from excavated underwater sites such as the Albenga wreck. After the fall of Rome, merchant vessels of this size were not built again in the west until the carracks of the sixteenth century.
Ships of the World: An Historical Encyclopedia
sunken civ, i shall post this to you in the first person.
after my empire collapsed, you puny mortals could not reach my achievments for another 1200 yrs or so. your entire western world is built on the dust of my bones, treat it well, for its a transitory thing.
Impressive.