In the U.S. Gulf, we don't normally do approaches over the water inbound, although we could. We have regular GPS approaches on land to our bases, with the MAP in a clear area, and VFR transition to the heliport at approach minima.
Offshore, we do either an OSAP (Offshore Standard Approach Procedure) or a HEDA (Helicopter Enroute Descent Area) procedure, depending on the situation. HEDA's are points that have been checked & have no obstructions in a 4NM radius circle, and we can descend to 400' as long as there are no radar targets. This should get us into VMC, after which we proceed using offshore VFR minima, which is 300'/2mi for multiengine helicopters. These are used when there is no weather station available, which is most of the time in my area. OSAP's require weather, and are flown to 200'/.7mi to a target (300/1 at night). What you are contemplating is likely our HEDA, and has to be at least 5 mi offshore here.