Olive Connecticut Sloop [Loring]
 Olive Branch Pennsylvania Brigantine [Cotton]
 Oliver Cromwell Massachusetts Brig/Ship [Coles Simmons Barr Bray]
 Oliver Cromwell Massachusetts Sloop [Tiley]
 Oliver Cromwell Pennsylvania Ship [Courter]
 Oliver Cromwell Rhode Island Ship [Chace]
 Otho Maryland Brig [Martin]
 Otter Pennsylvania Boat [Harvie]
 Oxford Maryland Schooner [Sherwood]