In the early 17th century attempts were made to further develop the agricultural produce trade with Bristol from Cardiff and from Aberthaw with a ferry trade in sheep and cattle and some Vale dairy produce is known to have made its' way to London via Bristol. Indeed Sir Edward Stradling and Lord Grey proposed a joint-stock company, at this time, to export Welsh butter to France via Aberthaw. In the mid-18th century the trade in agricultural produce and livestock with the West Country ports continued to flourish.
In the 17th and 18th centuries, too, Cardiff was providing crews for ships sailing to the West Indies and America.The activities of Sir Henry Morgan of Llanrhymney, the famous buccaneer, who became Governor of Jamaica, Sir Thomas Button of Worlton, who took commmand of the expedition to explore the North West Passage and discovered Hudson's Bay, Col.William Matthew of Llandaff, who became Governor-in-Chief of the Carribean Islands and Governor of the Leeward Islands, and Rear Admiral Thomas Matthew, Commander of the Mediterranean Fleet, resulted in many Cardiff and Vale of Glamorgan sailors being involved in naval activities in various parts of the world during the 17th and 18th centuries. Captain Richard Priest, the Cardiff boatowner, is known to have made three voyages to Africa, on the last of which he was killed on the Guinea Coast. Phillip James, another sailor, was captured by the Turks and imprisoned, eventually escaping and getting home to Llandaff, George and John Morgan were less lucky, being captured by the Spanish and dying in prison in 1783. The Rev. John Deere of Penllyn, Chaplain to Sir Cloudsley Shovel, narrowly escaped drowning when Shovel's Squadron went down off the Scilly Isles in 1708. Christopher Bassett, a Captain with Byng's Squadron in 1756, returned home to the Vale after spending some time as a Privateer.
By the early 1760s the channels leading to both the Old Quay and the GolateWharf were becoming silted to such an extent that vessels could only approach the quays at high tide, and the loss of custom dues eventually became acute enough for the Corporation to decide that improvements must be made, clearing the approaches, rebuilding the Quay wall and providing further accommodation for shipping along the river bank. At this time two Water Bailiffs were appointed to supervise the Quay and the navigation of the river and to enforce the payment of dues. The Lesser Quay near the Golate, the Cannon Wharf (so called because of its use in the boring, testing and export of cannon during the American War of Independence) and the Bank Wharf all came into use by 1788.