Alexander Gabrielsen aka Alexander Hadland

Looking for help please researching further details of life of Alexander, brother of Sigvart and Dina (see separate forums on this site) : - son of Gabriel Gundersen/Hadland and Anne Oline Tollaksdr - born Stavanger 21 Dec 1862 - 1865 census for Stavanger shows Alexander living with parents and elder brother Gunvald - merchant marine seaman, Stavanger seaman's roll number 5583. Signed off his ship in Surabaya (Indonesia) in 1881 - 1901 census for Ireland shows Alexander Gabrielsen with wife Mary and 3 children living in Belfast - 1911 census for Ireland lists Alexander Gabrielson (note spelling change) with wife Mary and 2 children living in Belfast, married since 1887 - Familysearch shows several children born, most dieing shortly after birth. Janett, Mary and David only survivors into adulthood ?? - Alexander works as merchant seaman on vessels out of Belfast, but not found on any crew lists. Awarded UK Merchant Marine Ribbon and Medal in 1919 and 1926 respectively for service in World War 1. Can find no record of marriage or death. Grateful for any help in filling in gaps