Helicopters at sea.
Don't know much about helicopters, but have always been impressed.
My question is, having seen Helicopters operate at sea landing on frigates I noticed them using some kind of winch device to attach the Helicopter to a grate of some kind on the stern whilst airborne.
To my uneducated eyes it would appear that this is to aid recovery in rough sea states, but am very curious as to how this works and the techniques used.
Thanks for any and all information.