The early trade of Glasgow made little use of the River Clyde that linked the town to the sea. The reason was quite simple. The river was shallow, meandering, filled with sandbanks and shoals and prone to floods. It could be crossed on foot at many points and those boats that did navigate its waters and tied up at a small quay built at the Broomielaw were very small. As Glasgow's overseas trade developed goods were therefore moved first by pack horse and then by wagon from anchorages such as the Fairlie Roads in Ayrshire and Newark near Greenock.
The need for a more secure port to serve Glasgow resulted in the town’s merchants approaching Dumbarton in 1667 only to be rebuffed. But only a year later land was acquired at Newark and soon Glasgow's ships were berthing at the new harbour of Port Glasgow.
As the roads linking the new harbour to the town were still poor much thought was given to ways of making the river more usable by barges and other small craft. Various attempts were made to remove the shoals, some of which had less than 0.4 meters of water over them at low tide. A more radical approach was put forward by John Smeaton (1724-1792) in a report presented to Glasgow Town Council in 1755. With the canal age then underway Smeaton proposed the construction of a dam across the Clyde near Renfrew which would raise water levels upstream. To allow ships to pass this dam early civil engineers proposed building a lock able to accommodate vessels of up to 100 tons. Despite strenuous efforts the construction of the lock and dam proved impossible in the fast flowing river. Attention was instead turned to the east and by 1777 Glasgow was linked to the Forth by the opening of a new canal.