Prairial was a supertanker, built in 1979 by Chantiers de l'Atlantique at Saint-Nazaire for . Prairial, which was the fourth and final vessel of Batillus class supertankers (the other three were Batillus, Bellamya and Pierre Guillaumat). She was the only ship of that class to have a career longer than ten years, sailing until 2003, although under different names: Sea Brilliance (1985), Hellas Fos (1986) and Sea Giant (1997). She is also distinguished as the third biggest ship ever constructed, surpassed in size only by Seawise Giant (later Jahre Viking, Happy Giant, Knock Nevis, and finally Mont) built in 1976 and subsequently lengthened, and her sister ship Pierre Guillaumat.