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The ship, in numbers

Record dimensions and published particulars. Imperial lengths are converted from the cited metric values.

Seawise Giant specifications with source references
SPECIFICATIONMETRICCONTEXT / CONVERSION
Length overall458.45 m131,504.10 ft
Beam68.80 m4225.72 ft
Laden draught24.61 m480.74 ft
Moulded depth29.80 m497.77 ft
Gross tonnage260,941 GT4Enclosed volume index
Maximum deadweight564,763 t23Carrying capacity
Net tonnage214,793 NT4Cargo volume index
Reported service speed16.5 kn630.6 km/h
PROPULSIONSumitomo Stal-Laval steam turbine6

Gross tonnage is an index of enclosed volume, not weight. Specifications span the enlarged tanker and later storage configuration. See the data notes ↓

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A place in the record books

LENGTH OVERALL

Longest self-propelled ship

458.45 metres

All-time record recognized by Guinness World Records.13

DEADWEIGHT

Largest carrying capacity

564,763 tonnes

Historical maximum deadweight, independently corroborated.23

Historical records, checked 8 September 2026. Seawise Giant is no longer in service. Exact succession dates are withheld while the lengthening chronology is reconciled.

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One hull. Many lives.

Seawise Giant was built to move crude oil on an extraordinary scale. An added cargo section made an already enormous tanker longer still. Its size also limited where it could operate. Later, as Knock Nevis, it found a new role storing and offloading oil off Qatar. 35

  1. Built in Japan

    Sumitomo Heavy Industries delivered the tanker at Yokosuka. The record dimensions belong to its subsequently enlarged configuration.136

  2. A giant grows larger

    An additional cargo section increased its size. Lloyd’s Register Foundation dates this work to 1980; other accounts place its return to service in 1981.36

  3. Damaged in the Gulf

    An Iraqi air attack caused extensive fire damage. The ship was later repaired in Singapore.6

  4. Back at sea

    Returned to service, briefly named Happy Giant before becoming Jahre Viking.6

  5. A second life as Knock Nevis

    Converted to a floating storage and offloading unit for the Al Shaheen field off Qatar.45

  6. The final chapter

    Renamed Mont for its last voyage, the tanker was dismantled at Alang, India.2

ALSO KNOWN AS

Happy Giant · Jahre Viking · Knock Nevis · Oppama · Mont2

Selected ownership & flag history

These are documented periods, not a complete registry history.

  • 2004–2009 · First Olsen Tankers45
  • 1991–2004 · Flag: Norway6
  • 2009–2010 · Flag: Sierra Leone6
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Reading the numbers

Good records need context. Here is what the figures do, and do not, tell us.

Which “largest”?

Length, carrying capacity and enclosed volume measure different things. This page identifies the self-propelled ship length record and the historical deadweight record, not a current operating vessel or a gross-tonnage record.12

Specifications depend on the date

Guinness records a maximum deadweight of 564,763 tonnes. The later Knock Nevis particulars report 564,650 tonnes. The beam here follows those particulars at 68.80 metres; Wikipedia lists 68.6 metres. These figures are not silently combined into a claim about one surveyed condition.246

A partial historical record

Only sourced flag and ownership periods are listed here. Missing years do not imply continuous ownership or registration. Exact record succession dates await reconciliation of the lengthening chronology.63

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Follow the sources

Every specification links to its reference. The headline records are checked against two independent publishers.

  1. 01
    Guinness World RecordsLongest ship ever

    Record length, original delivery year and final scrapping.

  2. 02
    Guinness World RecordsLargest ship (deadweight tonnage)

    Maximum deadweight, former names and scrapping at Alang.

  3. 03
    Lloyd’s Register FoundationMaritime science and technology: changing our world

    Independent confirmation of length and deadweight; dates the additional cargo section to 1980.

  4. 04
    Marine Marchande / Jacques DraoulecLa fin du plus grand bateau du monde, le Knock Nevis

    IMO number, beam, draught, depth, gross and net tonnage; floating-storage conversion. Reports a different later deadweight.

  5. 05
    Ganger Rolf / Fred. Olsen ProductionAgreement to upgrade Knock Nevis

    Primary operator announcement confirming storage operations at Al Shaheen and the contract through 2009.

  6. 06
    WikipediaSeawise Giant

    Supporting chronology, machinery, speed and selected flag history. Not used as the sole source for the headline records.

Illustration & reuse

Jahre Viking: illustrated side profile of Seawise Giant under its later name. Illustration by Shipsprofiler, via Wikimedia Commons. Licensed under CC BY-SA 3.0. Resized and converted to WebP. Illustration, not a photograph. The image retains its original license.