A couple in their 60s were descending the famous flight of locks between New Springs and Ince when the bow end caught one of the walls, dipped down and began shipping water.
The occupants safely got off the boat but the oily water began flooding its front end.
When a crew from Hindley arrived on the morning of Sunday June 26, parking up on a nearby housing estate and walking the rest of the way, the craft was under water at one end.
They brought pumps which jettisoned the dirty water and the boat was righted again, but a spokesman for the fire crew said he thought the engine was damaged and fixtures and fittings would probably need replacing during a trip to a dry dock.
The boat could not be re-started but Canal and River Trust volunteers then arrived to tow it away so the canal could reopen.