The Dunkirkers had an extremely wide range for their era. Although mainly operating in and around the Channel, they also sailed near the Danish and German coastal areas to intercept Dutch ships returning from the Baltic, and operated in Spanish and Mediterranean waters. They cooperated closely with the Spanish navy, for instance, in the Battle of the Downs. This combined effort reached a peak of effectiveness during the time the Eighty Years' War merged with the Thirty Years' War. To evade the Dutch navy the Dunkirk admiralty had a special type of small and very maneuverable warship constructed, the frigate. Frigate-like ship types were soon adopted by other navies and still have their modern-day counterparts.