How did they get from England to America?

I have two familymembers emigrating from Norway to America. I have found both of them in passengerlists from Norway to England, but they changed ship in England, and I don´t know how to find them... 1) Jacob (Jakob) Jensen Herregaarden Left Norway with S/S Volo, May 5th 1905. Wilson Line. Arrived Hull in England, May 7th 1905. He could have taken a ship from Liverpool about May 8th 1905?? 2) Kristian (Christian) Jensen Herregaarden Left Norway with S/S Tasso (II), Sept 17th 1910. WIlson Line. I guess he arrived Grimsby in England about Sept 19th 1910. I don´t know how he got to US from there? Does anyone have any information?