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Seawise Giant

Seawise Giant was a ULCC supertanker and, by several measures, the largest ship ever built.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 27, 2026|2 min read| Fact-checked

Seawise Giant was a ULCC supertanker and, by several measures, the largest ship ever built. It was constructed in Japan in the late 1970s and later sailed under names including Happy Giant, Jahre Viking, Knock Nevis, and Mont. The vessel was eventually scrapped in India in 2010.

Design and construction

The vessel was built in Japan between 1974 and 1979 by Sumitomo Heavy Industries. It was designed as a ULCC supertanker with exceptional length and cargo capacity.

Service history

The ship changed names several times over its career, including Happy Giant, Jahre Viking, Knock Nevis, and Mont. It remained in service for decades before being withdrawn and eventually scrapped.

Size and records

Seawise Giant is commonly cited as the longest self-propelled ship ever built, with a length of 458.45 metres. It also held the record for the greatest deadweight tonnage recorded for a ship.

Final years and scrapping

After its commercial life ended, the vessel was sold for demolition and taken to Alang, India. It was dismantled in 2010.

Key facts

  • Seawise Giant is widely described as the longest self-propelled ship in history.
  • It is generally regarded as the largest ship ever built by displacement and deadweight tonnage.
  • The ship was built by Sumitomo Heavy Industries in Yokosuka, Japan.
  • It served under several names during its life, including Knock Nevis and Mont.
  • The vessel was eventually beached for scrapping in Alang, Gujarat, India.

Frequently asked questions

What was Seawise Giant?
It was a ULCC supertanker, a type of very large oil tanker.
Why is Seawise Giant notable?
It is widely described as the longest self-propelled ship ever built and one of the largest by deadweight tonnage.
Where was Seawise Giant built?
It was built by Sumitomo Heavy Industries in Yokosuka, Kanagawa, Japan.
What other names did it use?
It was also known as Oppama, Happy Giant, Jahre Viking, Knock Nevis, and Mont.
What happened to the ship?
It was eventually scrapped in 2010 after being beached in Alang, Gujarat, India.

References

  1. Wikipedia — https://en.wikipedia.org/wiki/Seawise_Giant
    Supports: Names, ship type, construction period, builder, location, and record claims
  2. Maritime Page — https://maritimepage.com/seawise-giant-the-largest-ship-ever-built-knock-nevis/
    Supports: Length, deadweight tonnage, and claim as largest ship ever built
  3. Simple English Wikipedia — https://simple.wikipedia.org/wiki/Seawise_Giant
    Supports: Construction year, service history, sinking/salvage, and scrapping