To answer Fareastdriver: agree that ro/ro terminals have a lot of heavy and hard-to-move stuff around, but it only needs a small unregarded item to get picked up in the downwash to do a lot of damage. Seem to remember that, not long ago, a helicopter was trying to land on a large yacht (I think in Norway?), when a lifeboat tarpaulin cover (that was allegedly lashed) got loose and flew into the rotor blades, bringing the aircraft down into the water. Something like a stray hi-viz jacket might do it. A good thorough check around the vicinity will certainly be needed before starting to spin the blades. But, hopefully, all will be well.