[2] In August 1943 US Admiral Harold R. Stark, commander of US Naval Forces Europe, ordered SC-683 and two other SC-class subchasers - SC-1061 and SC-718 - to be transferred to Britain.

When they arrived at the Naval Yard, the vessels' commanders were ordered to warn their crews to observe strict silence about their movements and were told that the three ships had been picked for a "special purpose".

[3] The three subchasers were hoisted aboard three Liberty Ships and secured as deck cargo and preparations made to transport them and their crews to an undisclosed location.

[2] The Hessa and her sister vessels superseded the famous fleet of civilian fishing boats that had formerly run naval operations between Shetland and Norway.

During the final two years of World War II the three ships performed a total of 114 missions to occupied Norway, and apart from one incident when a Canadian aircraft fired on Hessa, the voyages were uneventful and there were no casualties.