I have been looking at a copy of  A Glossary of Cornish Sea-Words, by R.Morton Nance, published by the Federation of Old Cornwall Societies in 1963.

It fell open . . .

The sing of the shore: the sound made by waves breaking, varying with the nature of the shore – sand, pebbles, boulders, scarped cliffs, or reefs and ledges of rock – and thus giving the experienced fisherman indication of his position when fog or darkness make land or lights invisible, Mousehole (J.G)

This was the sing of the shore of my boyhood.

(Images by Bill Whateley)