It is known from references from both the Second Punic War and the Battle of Mylae that the quadrireme had two levels of oarsmen, and was therefore lower than the quinquereme, while being of about the same width (). Its displacement must have been around 60 tonnes, and its carrying capacity at marines. It was especially valued for its great speed and manoeuvrability, while its relatively shallow draught made it ideal for coastal operations. The "four" was classed as a "major ship" ("maioris formae") by the Romans, but as a light craft, serving alongside triremes, in the navies of the major Hellenistic kingdoms like Egypt.