Brave Little Belgium motivated many in Britain and her Empire to enlist. Marines and Naval troops were the first to come to assist the Belgians at Antwerp, and their Navy's artillery helped to stop the German advance at Nieuport, on the river Yser. The North Sea became a new front line where the Dover Patrol came to the aid of the Belgian, French and British troops with warships, heavy artillery in the dunes and new fighter planes, showing the importance placed on fighting the German U-boat bases at Zeebrugge and Ostend from the sea as well as from land.