Here's some lines from Bilbo's Last Song by J. R. R. Tolkien
...
Farewell, friends! The sails are set,
the wind is east, the moorings fret.
Shadows long before me lie,
beneath the ever-bending sky,
but islands lie behind the Sun
that I shall raise ere all is done;
...

The last line says "that I shall raise ere all is done", but what shall he "raise"? Would it mean he shall raise "that"(the sun or the island in the previous line), or raise himself, from the bed? I checked every dictionary for the definition of "raise", still can't make sense of it. I really enjoy reading JRRT's Middle-earth, often my poor English won't help though:(

Thanks in advance.
Here, raise = see, arrive at. It is a nautical term.
Thanks a lot!

Still one more question. Is there any special term in "the moorings fret" too? I don't really understand what this phrase implies. Should it be interpreted as "the ship-mooring equipments or place are worrying, anxious or irritated"?
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The moorings fret = the ship is eager to leave (its ropes are chaffing on the posts they are tied to).
So the ropes are biting the posts. Got it.

Thanks again!