A model of a Roman Merchant Ship of the first century A.D. that is on display in the Malta Maritime Museum.
Roman Cargo ships were rounded vessels with a forward leaning fore–post, a high stern and a high bent stern post that was often decorated in the form of a swan's neck. Some were at least 180 feet long and could carry tons of cargo: wheat, oil, wine, grinders, statues, etc.!
These ships were known as "Alexandrian Ships" because these large vessels carried wheat from Egypt to Rome!
It is well to remember that Paul traveled on two such ships on his journey to Rome—via shipwreck on Malta (Acts 27:6; 28:11).
To view a large, but less than full, modern reconstruction of such a cargo ship see Here.