The crew remained aboard the ship

The 12 passengers were on board The Claymore ferry when it got into difficulty near St Margaret's Hope Bay, on South Ronaldsay, just after 2000 GMT.

A coastguard spokesman said the ferry, which is operated by Pentland Ferries, stopped moving when an unknown object became entangled with one of its propellers.

Shetland Coastguard co-ordinated a rescue operation involving the Longhope lifeboat to take the 12 passengers off the vessel.

They were taken to a nearby ferry berth on Orkney.

The spokesman said: "We are unsure if the ferry was leaving or returning to Orkney when it lost power and stopped moving.

"All 12 passengers were taken off as a precaution. There are no injuries."

Ten crew members remained on board and the vessel docked safely before midnight.