Any limit as to RV length on the Alaska Ferry

I watched a large class A unload in Skagway, about a decade ago. The tide was way down, and the rig had to transition from a floating platform attached to the hull, to a very steep ramp. He started forward and began dragging the lower lip of the front cap. He stopped, with a full load of trucks, RVs and cars behind him, and the dock hands told him that he had no choice but to gun the throttle and keep moving. I don't know how badly it cracked and mangled the front cap, but it was an ugly scene to witness.