WWI – German U Boats a fine German issue poster, showing in graphic terms the numbers of British and allied vessels destroyed by German U Boats up to 1917. The poster shows a map of the British Isles with each vessel indicate in black, with a quotation from Sir Arthur Yapp which in translation reads : ‘I am appalled at the escalating effects of the undersea war on our economy.’ The poster is in good fresh condition. Approx 38x26ins.