I saw one animation that described a smaller channel opening up to the main channel to the ship’s starboard. The opening can cause a slight drift to starboard. No problem with engines and control of rudder, but that’s right where the power failed.
“What’s Going On With Shipping” thinks there may have been flow (current) coming out of that channel, and with little or no way to compensate, that current may have kicked the stern of the ship back into the main channel, turning the ship right into the bridge support.