Ship of the line
Ships of the line evolved from the galleon whose strength and defensive power grew during the transition from the 17th to the 18th century.
In capacity they ranged from 500 to 1000 tons. They had three masts with square sails and an aft mast with lateen sails.
The forecastle essentially disappeared, as it was no longer useful, and the height of the aftercastle was reduced. Ships of the line were longer and slimmer, and their two or three decks ran parallel to the waterline. They could be heavily armed with a great number of guns, from 50 to 120.