Few navigational aids have been established among Cuba’s reefs. Therefore, navigation in the coral waters is almost entirely dependent upon visual sightings through the water and the sea conditions for which reefs can easily be seen.
Coral heads will be seen sooner and more easily if the height of the observer is as high as possible above sea level and also when the sun is high and behind the observer—an elevation of 20 degrees is best. The ideal sea condition is when the sea is ruffled with a light breeze. When seas are glassy calm it is extremely difficult to distinguish the colour differences between shallow and deep water. The use of polaroid sunglasses is strongly recommended as they make the variations in water colour stand out more clearly.
The colour/depth correlation may seem difficult at first but soon it soon becomes second nature and almost without thought. In tropical water, an area with a covering depths less than 1 m (3.3 ft) will appear to be a light brown colour. Areas with a covering depth of 2 m (6.5 ft) or more will appear to be light green. This colour will deepen to a darker green in depths of about 6 m (20 ft), and finally to a deep blue for depths over 25 m (80 ft).
Floaters (a cloud’s shadow on the sea surface) are indistinguishable from reefs, with practice you will know which are clouds and which are coral heads.
The edges of coral reefs are usually more uniform and therefore more easily seen on their windward or exposed sides, while the lee sides frequently have detached coral heads not so easily detected—polarized glasses and eyeball navigation becomes essential.