GC Rieber Shipping has completed the sale of its icebreaking research vessel Ernest Shackleton (built 1995).

The buyer has been revealed as Italy's Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), the seller said on Thursday.

No sale price has been disclosed but GC Rieber said it expects a positive cash effect of around NOK 140m ($16.4m) when plans to sell the vessel were announced in March.

The research vessel has been on charter to the British Antarctic Survey (BAS) since May 2000, but was redelivered to its owner earlier than scheduled this year so that it could be sold.

"The Ernest Shackleton has been chartered back to GC Rieber Shipping during North Sea summer seasons, providing GC Rieber Shipping with flexible tonnage during periods of high demand and BAS with additional charter hire," said Christoffer Knudsen, GC Rieber's chief commercial officer.

The ship was used primarily as a logistics ship for resupplying BAS’s stations in the Antarctic.