Leth from Arendal

My mothers paternal family are Leths from Arendal Aust-Agder Norway. My GG Grandfather George Emily Leth (Known as Georges Emil Leth) reportedly arrived in Port Adelaide Australia about 1871and jumped ship at the age of 16 before running away to the NSW goldfields and settling in Sydney in the late 1800s. The ship was a norwegian merchant ship supposedly captained by his father. His death certificate aged app 90 y.o. in 1945 states his fathers name as Samuel Nicholas Leth and his mother as Marion Georgina Leth. I have uncovered evidence of a marriage on 25 FEB 1851 at Arendal, Aust-Agder, Norway between Samual Nicolai Leth and Maren Gurine Jensdr. This has to be Samuel and Marion. As yet I haven't uncovered any trace f their families in Norway and there's no evidence of them coming to Australia. My mother had a family tree showing Georges father as a Hans Leth Ships Captain, brother to Frederik custom officer and Neils ship broker of riga as well as sisters Maren Cecilie spinster and Catharine Helmer (Kitty) who married Consul Marten or Morten Kallevig. Their father was Isaac Leth from Arendal and husband to Marthe Sophie Willumsen Daughter of Niels Willumsen shipowner and proprietor of Hogedal, Arendal I am stuck with Samuel, father of young George the runaway. Is he really Hans leth the ships captain or is this family history incorrect as there is evidence of a Samuel Leth marrying in ARENDAL IN 1851. Is there another Leth family sea captain from Arendal ?? Was samuel a 4th son in the family Leth of Arendal and what ship did he captain to Port Adelaide more than once during the period 1850 - 1880. If i can discover the true identity of Georges father I can then confirm my mothers research or take a different direction. If anyone can help please post a reply.