What major waterway influenced the increasing size of tankers due to interruptions in a vessel's ability to transit?

The Suez Canal has been a significant factor in the evolution of tanker size due to its strategic position and the implications of transit interruptions. The Suez Canal connects the Mediterranean Sea to the Red Sea, providing the shortest maritime route between Europe and the lands lying around the Indian Ocean and western Pacific oceans.

When the canal is closed or its usage is restricted, such as during conflicts or maintenance, vessels must take much longer alternative routes around Africa, like the Cape of Good Hope. This reality emphasizes the need for larger tankers that can carry more cargo to offset the higher costs and longer transit times associated with these detours. As tanker technology advanced, many operators capitalized on the efficiency and economy of scale that larger vessels could provide, leading to the construction of very large crude carriers (VLCCs) and ultra-large crude carriers (ULCCs).

Other waterways, such as the Panama Canal, play a significant role in global shipping, but their influence on tanker size is not as direct as that of the Suez Canal. The Bering Strait and the Strait of Gibraltar, while important navigational channels, do not have the same impact on tankers in terms of size adaptation due to transit interruptions.