There seems to be a lot of criticism/speculation, but could it be a hand held line from the pax seat, helping to secure the boat landside? Simple procedure to snag the boat with the grappling hook, then pay out the line as the R44 is hover taxied to the shore where the line is then passed to be secured.
I realise that the handrail wouldn't be the strongest point on the boat, but as an interim solution to securing the boat, I'd say that it would make a lot of sense, and wouldn't be nearly as risky as a lot of posts here seem to imply.
Quote from the Enquirer:
Rescuers worked for several hours securing the white-and-blue craft as it rested sideways against the dam. Eventually, the boat was pulled onto rocks at the river's western shore.