The Moorings Four(4) Hour Guarantee is really very telling on what is reasonable to expect:

What's Covered

The following equipment is considered essential to the operation of the yacht and is covered: engine, transmission, windlass, sails, standing and running rigging, battery and alternator.

What this Guarantee Does Not Cover

All breakdowns will be serviced. However, compensatory sailing time will not be provided for repairs to the following items: cellular phone, VHF, refrigeration, stereo/cassette/CD player, auto pilot, GPS, water pressure pump, dinghy, outboard, knot meter, depth sounder, air conditioning and any other item which does not render the yacht inoperable. The Moorings or Moorings Preferred Partner will make every effort to repair these types of problems as soon as possible, if the charterer chooses; however, charterers may be asked to move to an anchorage that is more accessible to our repair team.
Also excluded from this compensatory guarantee are any breakdowns that occur outside the twenty-mile radius of a Moorings or Moorings Preferred Partner base, voyages into USVI waters or chartering to Bimini from Miami, and problems resulting from the negligent operation of the charterer.