M/Y Callisto pictured in Santorini

(4:10 p.m. BST) -- Variety Cruises has been forced to cancel its summer 2017 Iceland programme on the 34-passenger Callisto -- one of the line's eight motor yachts -- due to damage caused to the ship as it refuelled.

The ship was repositioning from Panama to Iceland when the incident occurred earlier this month in preparation for the June to September season.

No passengers were onboard the ship at the time and despite numerous attempts to determine exactly when and where the incident took place, these details are still unclear.

Variety Cruises has revealed that the ship returned to Panama for a dry dock assessment of the damage and to allow repairs to take place.

In a statement, the line said: "Callisto suffered a grounding accident during refuelling on her empty (crew only) positioning voyage to Iceland from Panama, and the vessel's stabilizers were severely damaged.

"After damage assessment it quickly became apparent that with the time required to manufacture, transport and fit the replacement stabilizers, complete repairs, test, plus positioning from Panama to Iceland, and with no replacement vessel available, the company had no option but to cancel the [summer] programme."

Passengers booked on one of the ship's summer sailings have been offered a full refund, with 25 per cent off a future cruise booking or the option to book an alternative sailing on a different Variety Cruises' ship -- including the option to transfer to the 2018 Iceland cruise programme on the line's M/S Panorama.

The line has issued 250 euros of onboard credit to all passengers who transfer to a different sailing and covered the cost of any passengers' cancellation charges on booked flights or other travel arrangements.

Callisto will resume sailing with its 2017/18 Panama and Costa Rica winter programme. The ship will offer a series of seven-night itineraries from Panama City through April 7, 2018, before repositioning to Eastern Europe.

From April 2018 Callisto will offer Croatia, Montenegro and Adriatic cruises out of Dubrovnik.

--By Kerry Spencer, Editor, U.K