The MoD has bareboat chartered the 3,700-dwt HMS Protector tosupport the Royal Navy in the South Atlantic and Antarctic since April 2011.
GC Rieber Shipping will book a gain of NOK 370m while the casheffect is NOK 485m ($81m), the Oslo-listed owner told the stock exchange.
This is the second time the MoD has purchased a chartered invessel from GC Rieber following the HMS Endurance.