Ingebrigt Andreasen Riisvigen and family

My name is Gary Anderson and I'm attempting to find the ship that my great great grandfather Inebrigt Andreasen Riisvigen 40 ( Engibright Anderson) his wife Anna Frantzdatter Riisvigen 49 ( Anna Frantz Anderson ) and there children Andreas Oluf Riisvigen 15 ( Andrew Olaf Anderson ) and his sister Olea Margrethe Ingibrigtsdatter Riisvigen 17 ( Lea Anderson ) arrived on. They were from Nord-Trondelag, Grong Parish Norway and if the citizen ship papers I have for Andrew are correct arrived in New York in August of 1881, family verbal history calls for an 1882 or 1883 arrival date. I know that Riisvigen was there farm name but so far I have had no luck in finding the ship and or route they took in coming to America. Any help would be great.