He was considered to be one of the country's leading naval architects of iron and steel ships.

Among his designs were the British passenger liner SS Britannia (1887) and the Norwegian barque Skomvær (1890).

After a short stay at the shipyard Flages verft in Bergen, he went to the UK to work for the shipbuilding firm Raylton, Dixon & Co. at Middlesbrough.

In 1889 Hansen was offered the management of Fevigs Jernskibsbyggeri, a new iron shipyard in Fevik at Grimstad in Aust-Agder.

During the next twenty years, over seventy steel vessels were designed by Randulf Hansen.