Maybe that's why the transfer is so expensive if they have their own seaplane (a De Havilland DHC-6-300 Twin Otter) & not a yacht after all?
Seems unlikely of course when a speedboat would be more convenient for such a short trip.
Interesting that it is owned by Trans Maldivian Airways & doesn't seem to have made any stops at the Waldorf to date, so maybe it is just paid advertising?
www.flightradar24.com/data/aircraft/8q-tmg
Update:
Yep, the plane is built in 1978 (with an interesting history!) & this website seems to indicate it is just advertising:
http://twinotterarchive.com/DHC-6_597.html