USS Shadow III (SP-102) was an armed 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...

 that served in the 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...

 as a patrol vessel from 1917 to 1919.

Shadow III 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 in 1916 by the Purdy Boat Company

Purdy Boat Company

The Purdy Boat Company, of Port Washington, Long Island, New York was one of the most famous makers of custom yachts and racing boats in the 1920s and 1930s. The name "Purdy" evokes a bygone era of classic race boats and cruisers custom designed and built by James Gilbert Purdy's sons, Ned and Gil...

, at Miami

Miami, Florida

Miami is a city located on the Atlantic coast in southeastern Florida and the county seat of Miami-Dade County, the most populous county in Florida and the eighth-most populous county in the United States with a population of 2,500,625...

, Florida

Florida

Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

. The U.S. Navy purchased Shadow III from Purdy on 12 June 1917 for use as a patrol boat

Patrol boat

A patrol boat is a relatively small naval vessel generally designed for coastal defense duties.There have been many designs for patrol boats. They may be operated by a nation's navy, coast guard, or police force, and may be intended for marine and/or estuarine or river environments...

 during 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...

. 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 4 September 1917 as USS Shadow III (SP-102) with Ensign

Ensign (rank)

Ensign is a junior rank of a commissioned officer in the armed forces of some countries, normally in the infantry or navy. As the junior officer in an infantry regiment was traditionally the carrier of the ensign flag, the rank itself acquired the name....

 Charles D. Mack, USNRF, in command.

Shadow III patrolled the Florida coast off Miami during World War I. After the war, she acted as an aircraft

Aircraft

An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

 crash boat for Naval Air Station Miami, Florida.

Shadow III was decommissioned

Ship decommissioning

To decommission a ship is to terminate her career in service in the armed forces of her nation. A somber occasion, it has little of the elaborate ceremony of ship commissioning, but carries significant tradition....

 at Miami on 25 January 1919. The Navy delivered her to the Parris Island Marine Corps Base

Marine Corps Recruit Depot Parris Island

Marine Corps Recruit Depot Parris Island is an military installation located within Port Royal, South Carolina, approximately south of Beaufort, the community that is typically associated with the installation. MCRD Parris Island is used for the training of enlisted Marines...

 at Parris Island

Parris Island, South Carolina

Parris Island is a former census-designated place , currently a portion of Port Royal in Beaufort County, South Carolina, United States. The population was 4,841 at the 2000 census. As defined by the U.S. Census Bureau, Parris Island is included within the Beaufort Urban Cluster and the larger...

, South Carolina

South Carolina

South Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...

, on 1 August 1919 for further non-commissiomned service.

In December 1919, Shadow III was taken to the Charleston Navy Yard at Charleston

Charleston, South Carolina

Charleston is the second largest city in the U.S. state of South Carolina. It was made the county seat of Charleston County in 1901 when Charleston County was founded. The city's original name was Charles Towne in 1670, and it moved to its present location from a location on the west bank of the...

, South Carolina, for survey. She was sold on 5 August 1921 to Mike Letiff of Charleston.