Sea-longing

[HerenIstarion]

having not so much to add as a comment, I would be glad to give some beautiful quotes:

S77

But mostly Ulmo speaks to those who dwell in Middle-earth with voices that are heard only as the music of water

S77

Long they remained by the coasts of the western sea, and Ossë and Uinen came to them and befriended them; and Ossë instructed them, sitting upon a rock near to the margin of the land, and of him they learned all manner of sea-lore and sea-music. Thus it came to be that the Teleri, who were from the beginning lovers of water, and the fairest singers of all the Elves, were after enamoured of the seas, and their songs were filled with the sound of waves upon the shore.

S77

There Tuor made a song for Eärendil his son, concerning the coming of Ulmo the Lord of Waters to the shores of Nevrast aforetime; and the sea-longing woke in his heart, and in his son's also

It seems (personal opinion) to me that water is of all created things mostly reminding of the Great Music, for See and Song are always related with Tolkien. In Elves it awakes the longing of the past, nostalgy of things that were before, and in Men the wish to depart whither they do not know. And sea-longing is evoked by the remnants of Ulmo's voice in the waves.