I have never sucked the rope on my challenger, probably helps that I have a tower. But I was with my buddy when he got the ski rope sucked tight into his Speedster. We had four guys, all pretty good swimmers, and a good long knife, we took shifts but still it was impossible to get the rope free while bobbing around in the lake., By the time you got to the intake, and started to reach up inside, you were well out of breath.
We got a tow, put it on the trailer, and were able to remove the final piece of rope which because of the tremendous torque, was like cutting through steel.
We wasted a lot of prime daylight trying to do it in the water, I would recommend flagging down the nearest boater, and getting a tow to shore, preferably your trailer....Of course, keeping the ski rope on top of the water not running over it would be the easiest...