After Welsh's death, William Saunders settled his family down in Placentia, so he could direct the business of Welsh's firm from there.
The enterprise expanded during the American war of Independence. New England substantial of trade to Placentia was disrupted and the Poole merchants turned to ports in the British Isles, particularly Waterford and the Southeast, for extra provisions. William Saunders finally moved his English base from his native Bideford down to Poole during the war. He had depended largely on North Devon Ship owners and Sea Captains for freight to Placentia. Saunders now purchased some of these vessels but also began building ships at Placentia during the winters. By 1780 the firm had 7 or 8 ocean going vessels engaged in the trade and one of the leading shipowners in the fishery.
Encouraged by a growing fishery in the 1770's William Saunders consolikdated and expanded the properties and trade bequeathed by Richard Welsh. Despite the intensifications and spread of settlement, seasonal and permanent along the southern coast, the harbour of Great Placentia maintained its monopoly over trade in the region. "If Placentia were to fall" an offical report in 1772, "it would destroy the fishery of twenty harbours."
Saunders was the principal merchant in this fishery and headed the only major house in the harbour. He established close links with the military, particularly during the war, securing contacts to carry supplies from St. John's and elsewhere to the garrison at Placentia. Saunders also secured material from the military to defend the firms premises in the outhabours at Point Verde and at Marticott.