HMS H5, was a British H-class

British H class submarine

The British H class submarines were Holland 602 type submarines used by the Royal Navy. The submarines constructed for the British Royal Navy between 1915 and 1919 were designed and built in response to German boats which mined British waters and sank coastal shipping with ease due to their small...

 submarine

Submarine

A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...

 of the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

. She was sunk after being rammed by the British merchantman Rutherglen, mistaken for a German U-boat

U-boat

U-boat is the anglicized version of the German word U-Boot , itself an abbreviation of Unterseeboot , and refers to military submarines operated by Germany, particularly in World War I and World War II...

, on 2 March 1918. All on board perished.

Stoker Petty Officer Thomas Lloyd was among the casualties. He, and all the rest of the crew are commemorated on Panel 29 at Royal Navy Submarine Museum

Royal Navy Submarine Museum

The Royal Navy Submarine Museum at Gosport is a museum tracing the international history of submarine development from the age of Alexander the Great to the present day, and particularly the history of the Submarine Service from the tiny Holland 1 to the nuclear powered Vanguard class submarine...

. Also on board was US Navy Lt. E.W.F. Childs, who became the first US Navy casualty of the First World War. The wreck site is designated as a controlled site under the Protection of Military Remains Act.

A plaque commemorating the 26 who died was dedicated on Armed Forces Day 2010 in Holyhead