Landing powerful jets
on a flight deck
is fine if you're working on a huge carrier. Most of the rocking-and-rolling
motion is neutralized by the sheer size of the ship. Try landing
on a small boat with about five feet to spare between the rotor blades and a wall, in 20-knot crosswinds
and swells over 20 feet.
The flight deck of a small ship is not the most happy of places to work, but several times every day this scenario is played out by the naval forces of many countries.
In order to make the best of the worst conditions, a system called RAST was developed. If I recall, Great Britain worked on the system for years, and actually winch their helicopters to the flight deck. In the US Navy, it is used mostly as a guide to help the helo land exactly on target in a large hydraulic trap.
The RAST (Recovery, Assist, Secure, and Traversing) system uses a beartrap-like vise to help secure the helo to the deck. It is capable of removing a sailor's leg, and it is not to be trifled with. The SH-60B helicopter uses a special probe called (surprisingly) a RAST probe, which is extended several feet from the bottom of the midsection of the helo. An underpaid Boatswain's Mate uses a special tool to lock a large cable extending from the RAST trap to the center of the RAST probe. This cable helps guide the RAST probe to the center of the trap, which closes when the helo touches down and locks the helo to the deck. The helicopter is relatively secured, but can (and usually is) turning and burning during a refuel and crew swap.
When flight operations are over, the helo is centered in the RAST trap by maneuvering the helo fore and aft. When everything is centered, the rotor blades and the tail section of the bird are folded and the tailwheel RAST probe is lowered into a channel.
Now that the helo is folded and centered, the RAST trap is used to pull the helo into a hangar. The helo then is chained to several tie-down points and chocks are used on the wheels. During high seas, the helo thrashes against the chains, making passage next to the bird (or even working on it) dangerous.
When the next flight ops are scheduled, the bird is towed out, spread and is put through a daily and turnaround inspection.