South Africa's National Sea Rescue Institute (NSRI) has prevented a tanker grounding after it broke a tow rope en route to breakers.

The 47,000-dwt Order (built 2994) was being taken to Maputo for scrapping on Friday when its line separated, fouling the 443-gt, 2011-built Pacific Ocean Engineering tug AHT Carrier's motor and tethering it to the huge ship.

Both began to drift towards the coast, but were still at least 15 miles off at that point, the NSRI said.

Its St Francis Bay duty crew were alerted after the tug was unable to recover the rope, but maintained a watching brief.

"The tug boat investigated all possibilities to detach herself from the casualty vessel and to re-attach a towline," NSRI said.

Salvage divers had been activated from Cape Town but would take quite some time to reach the scene, as would the 2,100-dwt salvage tug SA Amandla (built 1976).

Urgent action needed

By the next morning, the tanker and the tug, with 14 crew onboard, were four miles offshore.

The NSRI then sent teams with two rescue crafts.

The two ships were found to be about two hours from running aground.

"All crew onboard the tug were safe but they were helpless without a tender boat to recover their towline from the water and with rope fouled around one motor leaving the Order at risk of running aground," NSRI said.

The teams found a cable lying in the water off the stern of the casualty vessel, with a chain and thick rope attached to it.

"The thick and very heavy rope that we found was hauled with great difficulty but successfully by our NSRI rescue crews onto the sea rescue craft," NSRI said.

"NSRI then rigged a patent line, using NSRI normal towing rope, and we were able to feed that patent line that we had rigged to the crew of the tug boat.

"The tug boat recovered their towline and stern to stern, on one motor, the tow ropes integrity was sound and the tug boat was able to hold the casualty ship by using her one operational motor from drifting."

They were both able to move slowly out to sea again.

The SA Amandla then took over the tow of the ship from AHT Carrier when it arrived later on Saturday.

TradeWinds reported last year that Order, then called Divine Order, was still in the fleet of Corinthians Shipping, the tanker arm of Nigerian oil trader Ontario Oil & Gas, which had started scrapping tankers.