ivers searching for U-boat wrecks in the English Channel off Devon, U.K.,, a forerunner of modern submarines. Commissioned in 1909, the lead British D-class warship in many aspects represented the design on which all future subs were based. The eight D-class submarines were noted for their pioneering use of diesel engines, twin propellers and torpedo tubes at both the bow and stern. They were longer and wider than earlier designs and had a range of nearly 3,000 miles, enabling them to put to sea instead of being relegated to shore patrol like predecessors. Despite its historical import, was scuttled in 1918 during target practice.
