Motor torpedo boat tender
From Infogalactic: the planetary knowledge core
Motor torpedo boat tender is a type of ship used by the U.S. Navy during World War II and Vietnam War. The motor torpedo boat tender's task was to act as a tender in remote areas for patrol boats (PT-boats) and to provide the necessary fuel and provisions for the torpedo boats she was responsible for. The type finds its root in the torpedo boat tender, developed in the 19th century.
This type of ship was classified as "AGP" and is sometimes called a "patrol craft tender."
Example of use
See USS Hilo (AGP-2) for a description of the functioning of this type of vessel.
References
This article incorporates text from the public domain Dictionary of American Naval Fighting Ships.