The third USS Ellen (SP-1209) was a United States Navy

United States Navy

The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...

 patrol vessel in commission from 1917 to 1919.

Ellen was built as a civilian

Civilian

A civilian under international humanitarian law is a person who is not a member of his or her country's armed forces or other militia. Civilians are distinct from combatants. They are afforded a degree of legal protection from the effects of war and military occupation...

 motorboat

Motorboat

A motorboat is a boat which is powered by an engine. Some motorboats are fitted with inboard engines, others have an outboard motor installed on the rear, containing the internal combustion engine, the gearbox and the propeller in one portable unit.An inboard/outboard contains a hybrid of a...

 of the same name in 1917 by the Herreshoff Manufacturing Company at Bristol

Bristol, Rhode Island

Bristol is a town in and the historic county seat of Bristol County, Rhode Island, United States. The population was 22,954 at the 2010 census. Bristol, a deepwater seaport, is named after Bristol, England....

, Rhode Island

Rhode Island

The state of Rhode Island and Providence Plantations, more commonly referred to as Rhode Island , is a state in the New England region of the United States. It is the smallest U.S. state by area...

, one of nine motorboats built to a common design for private owners in anticipation that their owners would make them available for naval service. The U.S. Navy acquired Ellen from her owner on 21 July 1917 for World War I

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...

 service as a patrol vessel. She was commissioned

Ship commissioning

Ship commissioning is the act or ceremony of placing a ship in active service, and may be regarded as a particular application of the general concepts and practices of project commissioning. The term is most commonly applied to the placing of a warship in active duty with its country's military...

 on 2 August 1917 as USS Ellen (SP-1209).

Ellen operated on section patrol

Section patrol

A Section Patrol craft was a civilian vessel registered by the United States Navy for potential service during and shortly after World War I....

 duty for the rest of World War I. She was returned to her owner in April 1919.

Ellen should not be confused with USS Ellen (SP-284)

USS Ellen (SP-284)

The second USS Ellen was a United States Navy patrol vessel in commission from 1917 until 1918 or 1919. Sources differ on most aspects of her history and even on her physical characteristics....

, another patrol vessel in commission at the same time.