there would be no direct boats from Island other than the vessels in the smuggling trade - these would not sail direct to North America but would usually be part of the triangular slave trade Liverpool etc to West Africa to West Indies/southern USA then possibly return with Rum etc or tobacco from Maryland - some of which cargo would be offloaded on Island for smuggling in smaller quantities.
Other import/export legitimate trade would be from British Ports (Liverpoool grew very much from early 18th C, Glasgow was a key tobacco importer, Belfast had a large textile export) to/from New York etc or Canadian ports