Complex sentence: Another son joined the United States Revenue Cutter Service, a predecessor of the U.S. Coast Guard, and achieved notability serving for more than 20 years along the 20,000 mile coastline of the newly acquired Territory of Alaska.
Split into simpler sentences: Another son joined the United States Revenue Cutter Service, a predecessor of the U.S. Coast Guard. He was notable for serving more than 20 years along the 20,000-mile coastline of the newly acquired Territory of Alaska.