The MV Loch Seaforth ferry limped back into Storoway port yesterday afternoon following a power outage during the journey between Ullapool and Lewis.
It is believed a problem with the main engine cooling system had caused the issue.
Limited power was achieved from one engine allowing the ferry, which had more than 340 people on board, to continue its journey.
RNLI lifeboats from Stornoway and Lochinver launched to the ship’s location approximately 17 miles south east of Stornoway.
The vessels reached the ferry around 2pm and escorted the vessel as she made her way, under her own power, to her journey’s end at Stornoway.
The Maritime and Coastguard Agency said the crew of an emergency towing vessel (ETV) had also been alerted to the situation.
A spokesman for Calmac said: “We experienced serious disruption on the Ullapool Stornoway route yesterday (August 8th) after a power failure on the MV Loch Seaforth during the 10.30am departure from Ullapool.
“The vessel successfully regained power and arrived in Stornoway around 4pm, approximately three hours behind schedule.
“After extensive sea trials the vessel was given Maritime and Coastguard Agency (MCA) permission to resume service and departed Stornoway for Ullapool at 10.13pm.
“We will continue to work to clear the backlog of traffic and apologise for any inconvenience caused. We would urge passengers travelling on the route to continue to check the website for the latest updates.
“Investigations into the causes of the power failure are continuing.”
The incident has lead to Western Isles MP Angus MacNeil making a renewed call for an Emergency Towing Vessel (ETV) to be stationed on the west coast.
Mr MacNeil said the UK Government needed to look at this emergency option once again, as the west coast is currently serviced by a vessel which also covers the Northern Isles.
He said: “It is lucky that the ETV, the only boat that could have assisted MV Loch Seaforth in the worst case scenario, was also on the west coast.
“However this shows that for now we need to have an ETV based in Stornoway in case of a similar incident in future.
“The tug is for unforeseen circumstances and unforeseen circumstances will happen. We need the insurance policy of a west coast tug.
“The UK Department of Transport are dodging their responsibilities here and crossing their fingers which is not good enough.”
Mr MacNeil has also contacted CalMac for an update on the status of MV Loch Seaforth following the incident.
He has made the case for an ETV time and time again and in 2016 presented a petition launched by local SNP councillors Rae Mackenzie and Gordon Murray to Downing Street.
The ETV in Stornoway was removed in 2011 as a cost cutting exercise by the UK Government.