Sources do sometimes state the ship type. Apostolos Delis created a dictionnary describing the rig and the hull of the most common ship types, providing also a few images and bibliographic references. This dictionary can be helpful also in providing assistance to researcher who are not specialist in naval construction and who might be blurred to see that a ship entering two ports in a relatively short time span was declared under two distinct ship-types. Whever the ship type concern a rig instear of a hull, this is likely.