Marine Glossary

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rock awash

On paper charts and RNC, the asterisk symbol rock is called a "rock awash," which in that case means it could cover and uncover with the tide, depending on the tide height and the rock sounding (drying height). Without a charted drying height, we cannot make any more specific predictions about the rock; we just know that in some cases it could be above the water and other times below the water.

Also on paper charts and RNC, the rock symbol of a plus sign with 4 dots signifies a very special rock that is right at the surface when the tide height is zero. This rock only shows when the tide is below zero. When the tide is zero this rock is just a ripple on the surface or maybe marks a small breaking wave in some cases.

The paper and RNC rock symbol of a plane plus sign means the rock is below the surface for any tide greater than zero, but in contrast to the 4 dots it is typically notably deeper than right at the zero tide surface, and sometimes a sounding will be given for it.

When we switch to ENC charts, the definition of rock awash changes. An ENC has only one kind of rock symbol, the asterisk, same as used in RNC, but this rock can be any one of the three described above. We learn the nature of the rock from a cursor pick