Vessels purpose-built to carry containers were used between UK and Netherlands [14] and also in Denmark in 1951.[24]:31 In the United States, ships began carrying containers in 1951, between Seattle, Washington and Alaska.[25] However, none of these services was particularly successful. First, the containers were rather small, with 52% of them having a volume of less than 3 cubic metres (106 cu ft). Almost all European containers were made of wood and used canvas lids, and they required additional loading[clarification needed] into rail or truck bodies.[24]:31–32