Lerwick Lifeboat went to the aid of a scallop dredger yesterday afternoon (Tuesday) after the vessel had reported trouble with her engine.
At the request of the Coastguard, an RNLI crew launched shortly before 4pm and found the vessel north of Whalsay.
The unnamed 16-metre vessel had problems caused by an overheating engine.
Crew from the lifeboat decided to take the stricken vessel under tow and return to Lerwick Harbour.
Coxswain Stephen Manson said the two-man crew had made the right decision to call for help.
Mr Manson said: “We were pleased to be able to assist and we’re glad that the vessel is now safely in harbour, rather than anything worse.”