This is a list of some of the world's largest ships by gross tonnage. Gross tonnage is a calculated value based on the ship's internal volume. Container ships the size of the Maersk Triple E class or larger would probably exceed these ships' gross tonnage if the volume of above-deck containers was included. Many of the world's longest ships are not particularly voluminous.
References
List of largest ships by gross tonnage Wikipedia(Text) CC BY-SA