5,500 TEU container ship assisted after 2-day drift off Australian coast | RIO MADEIRA

Container ship RIO MADEIRA lost power on Oct 20 while cruising off Sydney, waiting out for scheduled ETA Oct 25. The ship drifted almost due south along New South Wales coast, some 30 nm offshore. Tug SVITZER GLENROCK (IMO 9795866) was assigned, RIO MADEIRA was taken on tow in the morning Oct 22 to be towed to Sydney, ETA didn’t change. As of 0515 UTC Oct 22 caravan was underway at some 8-8.5 knots speed, not clear if the ship is on tow or already under own power.
The ship has 3380 containers on board. What’s the cause of power loss? Mechanical failure or fuels used and fuels shifts? We will never know, most probably.