Search filters: You can search for an individual ship or groups of ships.
Entering data in a field box restricts the search to match that criterion;
leaving a box blank will search all data in that field. Thus to find an
individual ship enter only one of IMO number, class ID number or name (or part
of name). To find groups of ships, fill in one or more of the appropriate boxes
(but not IMO number, class ID number nor name).