An emergency tug is assisting a cargo ship carrying salmon feed that lost power in stormy conditions off Taransay in the Western Isles.
MV Fame, which has five people on board, reported the loss at about 17:30 on Thursday.
Two lifeboats and the Stornoway Coastguard helicopter have been assisting the crew.
The coastguard agency’s emergency towing vessel, Orkney-based Ievoli Black, has ship under tow.
Stornoway and Leverburgh lifeboats went to the aid of the cargo ship on Thursday evening and remain at the scene.
MV Fame’s crew managed to deploy both the ship’s anchors in an effort to prevent the vessel from drifting.
The crew managed to do this in the face of winds gusting to force 10 and sea swell of up to 8m (26ft).
The Scottish Environmental Group, Marine Accident Investigation Branch (MAIB) and Secretary of State’s Representative for Maritime Salvage have been notified and have been monitoring the situation.
HM Coastguard commander Peter Davies said the weather conditions were still challenging.
He said: “The five crew currently onboard and the RNLI all weather lifeboats have been battling bad weather conditions all night to keep the vessel from grounding and we have so far managed to stabilise the vessel from drifting further.
“The vessel is currently six nautical miles from the Isle of Harris and we just established a tow this morning so the vessel can be taken to a safe shelter away from the prevailing weather conditions.”
Western Isles local authority, Comhairle nan Eilean Siar, said the incident had posed a potential pollution threat.
Roddie Mackay, leader of the comhairle, said it also highlighted the need for the Western Isles to have a dedicated coastguard emergency towing vessel (ETV).
Scotland used to have two of the boats available to the coastguard to cover the north and west coasts, before the UK government reduced the service to a single ship in 2012.
“These incidents are all too frequent and we remain very concerned, as do colleagues in neighbouring councils, about the current situation which increases the risks for mariners and the environment.
“We will once again be making the case to the UK government for a second ETV based on the west coast to address this serious issue.”
Western Isles SNP MSP Alasdair Allan has also renewed his calls on the UK government for an emergency tug to be reinstated to Scotland’s west coast.