Capt. Rolaf Olesen

I am seeking any info. on a Capt. Rolaf Olesen. He was married to Maren Torkelson around 1867 in Norway, place unknown. Maren was the widow of Johannes Hisholt who died in an accident around 1865. Maren had 5 children from her previous marriage: Carrie b.1856, Ole b.1858, Josephine b.?,John b.1862, and Theodore b.1864. Capt. Olesen, Maren, and the children emmigrated to the U.S. about 1873. By that time they were known by the Olesen surname. Sometime after their arrival in the U.S. their name changed to Olson. I have no info. on where they came from in Norway, but Marens first husband was supposedly from Skien, Telemark. I dont even know what kind of Capt. Rolaf was- naval or military. I have tried finding the Capt. on the Norway and U.S. sides with no results, any help would be greatly appreciated. Thanks, stevej