Seeking info on Knutsdatter of Hundsnes

My great grandmother was named Sanna Theodora Sofia knutsdatter of Hundsnes in Rogaland. 24 Mar 1873 birthdate She immigrated in 1892 I have found no ship list listing her. In America she choose Olson as her last name, and she immigrated in 1892. The state she came to was Iowa. I have a picture of her with her sister, but I have no name of the sister, she had many. She had many siblings and I have tried in vain to locate what happened to them if anyone could provide insight into this I would appreciate it. Takk, Amy Peterson