I'm no ex-helo pilot however researching 'how to deck land' for other aircraft types found some info about such things for helioplickers. Whether it is relevant today for flat decks I guess so. Go here:
FM 1-564: Shipboard Operations - Chapter 5
Found graphic attached in this 3.4Mb PDF [diff between USCG & RN approach]:
http://scholar.lib.vt.edu/theses/ava...omplete)v4.pdf