The reasons for HIFR you gentlemen who fly or flew the aircraft know as well as me, suffice to say I have seen a CVS with harriers at alert, both spots behind the island blacked and the graveyard full of bombs. Although in reality the usual reasons are long distance sorties (casevac etc) to a vessel with fuel but no deck, or to allow ship manoeuvring as described by Geoffers.
I supervised many HIFR evolutions from many ships and can clear up a couple of procedural points. The refuel hose is connected to the HIFR hose and this is hard connected to the deck (ring bolt etc) using a shackle. The HIFR hose is then flaked out on the deck in such a way that at no time will your team have to step over the hose or get “inside” (sea side) of the assembly. (Don’t stand inside a bight or coil)
The HIFR hose is marked such that the team and the aircrew can see how much hose is deployed over the side; the aim is to have as little as possible deployed as a hose full of fuel is heavy. The hose should ideally describe an upward curve to the aircraft as mentioned earlier by someone else, so the hose is constantly adjusted, taking fuel down below deck level only to pump it up again is not efficient.
Should the aircraft or ship pull away the hose has a break point that self seals, this leaves the aircraft with a section of hose hanging from the “heave ho” point on the winch which can be unhooked and lowered to the deck crew. The deck crew will have pulled in the disconnected hose, cleaned and checked it; they then reconnect to the business end, “con check” it and run a quick amount into the ship to ensure no possible contamination.
Then back to business.
If at any time the hose pulls violently the team are (well) trained to drop it, so the risk of pulling someone over the side should be minimal and de-rigging can literally be done in seconds, the slowest part being the hose retrieve from the aircraft, the rest is dropped into the cat walk or stowage and sorted later.
Cheers now