And now for the softer side of RotorHead:
There are Army helo units that maintain qualifications to land on ships. Here are a few to whet your appetite:
http://www.navy.mil/view_single.asp?id=73676
http://www.navy.mil/view_single.asp?id=74190
http://www.navy.mil/view_single.asp?id=76485
Reasons for this training can be as simple as providing options in a MEDEVAC situation to specific SPECWAR tasking. If you look in the NATOPS manuals for the Gators and Air Capable Ships, you will find wind envelopes for many non-Navy/Marine Corps aircraft.
Edit: As Clux4 so astutely pointed out, just cuz a helo crashes, doesn't mean it was necessarily pilot error.