auxiliarist
noun
aux·il·ia·rist (ˈ)ȯg-¦zil-yə-rist 
-¦zil-rist,
-¦zi-lə- sometimes -¦zi-lē-ˌer-ist
variants or Auxiliarist
plural auxiliarists or Auxiliarists
: a member of the United States Coast Guard Auxiliary
Note: The United States Coast Guard Auxiliary is an organization of civilian volunteers who provide various forms of support and assistance to the Coast Guard.
Once they are trained and certified, qualified auxiliarists perform regular safety patrol missions in their area and may support the Coast Guard in environmental protection, commercial vessel safety inspections, port security and planning, licensing and documentation and other operational roles. 
Liz Barrett, Contra Costa Times (California), 29 Dec. 2011
Liz Barrett, Contra Costa Times (California), 29 Dec. 2011… also volunteers with the U.S. Coast Guard Auxiliary at Ellington Field, where he is training to assist the recreational boating community, help with search and rescue, and is working to establish a program to help auxiliarists deal with the stress of their duties. Robert Stanton, Houston Chronicle, 11 Sept. 2008
Robert Stanton, Houston Chronicle, 11 Sept. 2008
Word History
Etymology
auxiliary entry 2 + -ist entry 1
First Known Use
1943, in the meaning defined above