After graduation from the Coast Guard Academy in 1928, Captain Rhodes served in the cutter USCGC Mojave (WPG-47) on international ice patrol. He was then ordered to flight training and later back to sea duty in the USCGC Perseus (WPC-114). In 1935 he was navigation officer in the USCGC Northland (WPG-49), built with a steel ice-breaking hull for an Arctic Alaskan cruise. She replaced the USS Bear (AG-29), transporting public health nurses and school teachers to Eskimo villages, carrying scientific expeditions, and handling law enforcement in the area. During World War II, he was XO in the transport USS General M.C. Meigs (AP-116) taking Brazilian troops from Rio to Naples. In 1945 he served as CO of the Coast Guard-manned attack cargo vessel USS Theenim (AKA-63), assisting in the occupation of Japan. There were several interspersed tours at Coast Guard Headquarters, and his final assignment before retirement in 1955 was Chief of Operations for the 14th Coast Guard District in Honolulu.