HMS Arno was a unique destroyer

Destroyer

In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...

 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...

 that saw service and was lost during First World War

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

. She was under construction in Genoa

Genoa

Genoa |Ligurian]] Zena ; Latin and, archaically, English Genua) is a city and an important seaport in northern Italy, the capital of the Province of Genoa and of the region of Liguria....

, Italy

Italy

Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

 for the friendly Portuguese Navy

Portuguese Navy

The Portuguese Navy is the naval branch of the Portuguese Armed Forces which, in cooperation and integrated with the other branches of the Portuguese military, is charged with the military defence of Portugal....

 as Liz in 1914 when she was bought by the Royal Navy for service in the Mediterranean

Mediterranean Sea

The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...

. As such she joins the Town-class

Town class destroyer

The Town class destroyers were warships transferred from the United States Navy to the Royal Navy and the Royal Canadian Navy in exchange for military bases in the Bahamas and elsewhere, as outlined in the Destroyers for Bases Agreement between Britain and United States, signed on 2 September 1940...

 of the Second World War

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

 as the only other Royal Navy destroyer type not designed and built in the United Kingdom

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

.

She had two funnels and masts and four QF 12-pounder gun

QF 12 pounder 12 cwt naval gun

The QF 12 pounder 12 cwt gun was a common calibre naval gun introduced in 1894 and used until the middle of the 20th century. It was produced by Armstrong Whitworth, Elswick and used on Royal Navy warships, and exported to allied countries...

s, shipped sided on the forecastle

Forecastle

Forecastle refers to the upper deck of a sailing ship forward of the foremast, or the forward part of a ship with the sailors' living quarters...

, behind the second funnel and on the quarterdeck

Quarterdeck

The quarterdeck is that part of a warship designated by the commanding officer for official and ceremonial functions. In port, the quarterdeck is the most important place on the ship, and is the central control point for all its major activities. Underway, its importance diminishes as control of...

. Although much smaller and slower than her British contemporaries, she was soundly built and had a high freeboard and tall bridge, making her a useful vessel. She was lost off the Dardanelles

Dardanelles

The Dardanelles , formerly known as the Hellespont, is a narrow strait in northwestern Turkey connecting the Aegean Sea to the Sea of Marmara. It is one of the Turkish Straits, along with its counterpart the Bosphorus. It is located at approximately...

 after a collision with the Acorn- / H-class

Acorn class destroyer

The Acorn class was a class of twenty destroyers of the Royal Navy all built under the 1909-1910 Programme, and completed between 1910 and 1911...

destroyer on 23 March 1918.