This romantic drawing shows barges on the River Thames with the masts of a sailing ship behind. Thames barges were used to transport cargo around the Thames and Medway. Their principal feature is the sprit mainsail, which differentiates them from every other type of vessel. The heavy wooden sprit is healed at the foot of the mast with its head at the peak of the mainsail. They usually carried a crew of three - a skipper, a mate (often under the age of 21) and a dog. Spritsail barges evolved with a very simple rig which, despite its size, could normally be easily managed by just two people. Rather than having to lower the sprit mainsail, it could easily be brailed up to a point just under the masthead. As a young man, Wyllie lived upon a barge on the Thames and converted it into a floating studio.