The command "heli enableRopeAttach false" do not disable the "Hook" action for helicopter.
According to the Biki : "Enable/disable ability to attach or be attached to ropes for given vehicle"
BUT the command has effect only if executed on the attached object. NOT if used on the object which will attach.
Create a mission with :
Put this in a "watch line" in console : heli canSlingLoad submarine
It returns true.
Then execute this in the debug console :
heli enableRopeAttach false;
The "watch line" now returns false.
Take off with the helicopter and try to "Hook" the submarine. The action is ALLOWED.
It only work if we execute this :
submarine enableRopeAttach false;