I am no engineer so this is a very unprofessional thought.
Tie a small but wide boat off from both sides to keep the boat centered, bow facing upstream and working off the back of the boat use timber claw hook on a winch and winch them back to shore you would need a floating throw line (sky rope) to return the hook back to the boat.
You would need something like an aircraft crash barrier net downstream should the mess break loose.
Whatever you decide .... Good luck
Tie a small but wide boat off from both sides to keep the boat centered, bow facing upstream and working off the back of the boat use timber claw hook on a winch and winch them back to shore you would need a floating throw line (sky rope) to return the hook back to the boat.
You would need something like an aircraft crash barrier net downstream should the mess break loose.
Whatever you decide .... Good luck