Which two cities in the middle atlantic colonies we're important centers of shipbuilding?

As early as the 1640s Swedish boat builders fabricated several small craft on the Delaware River in their short-lived New Sweden colony, but large-scale shipbuilding started when William Penn (1644-1718) settled his great proprietary grant of Pennsylvania between 1681-1682 with skilled Quaker artisans and maritime merchants escaping the religious persecution (sufferings) in old Britain and seeking economic opportunity in the New World. In fact, six years before he founded Philadelphia, Penn had helped shipwright James West (d. 1701) develop a small shipyard in 1676 along the Delaware Riverfront in what later became Vine Street in the city of Philadelphia. Meanwhile, Penn recruited Welsh, Irish, Scot and English Quaker craftsmen who were involved in shipbuilding in Bristol, England, and more fully along the Thames River, already by 1682 a great center of ship construction and merchant houses. Indeed the Southwark section of London’s Thames riverfront soon gave rise to the Southwark shipbuilding and merchant community along the Delaware riverfront of Philadelphia. When the Philadelphia riverfront became too crowded with merchant docks and buildings for establishment of shipyards, many shipwrights moved a few miles upriver to the Kensington neighborhood that soon rivaled Southwark as a shipbuilding center on the Delaware River.