1869 & 1871 passengers: Norway to USA/Canada

Looking for ship that Lars Larsen Dale came to US on in 1869. Destination was Iowa. His future wife, Martha Einarsdt, came over in 1871. They both lived in Stord, Hordaland, when they emigrated. He was born in 1850 and she in 1849. They married in Iowa in 1873. Any help appreciated. I know that there are not many passenger records available for this period. Thanks, Phil