Imagine your boat entering the
calm, turquoise water of a lagoon.
Outside, the swells you
just sailed through explode on the
fringing coral reef. In this cruising
paradise — typical in the tropical
Pacific and Indian oceans —
the water is so clear that at 20, 40
and even 60 feet deep, the bottom
holds no secrets. At the anchorage,
this transparency reveals a mostly
white-sand bottom interrupted by
stand-alone coral structures, called
bommies, that rise like cactuses
from a desert floor.