Earliest name of the swan have of the Sea Elves, appearing both with (LT2/82) and without (LT1/164) the genitive suffix -n.
Early Quenya
alqalunte
proper name. Swanship
kópas alqalunte(n)
place name. Haven of the Swanships
There are more words but they are from Tolkien's earlier conceptional periods. Tolkien likely changed these words as he evolved the aesthetics and completeness of the languages. You may even find languages that Tolkien later rejected. Do not mix words from different time periods unless you are familiar with the phonetic developments.
Below: Tolkien's Late Period (1950–1973). These are from Tolkien's late conceptual period — his most settled forms of the languages. Prefer these over the earlier ones above when composing new text.
The swan ships from Kópas Alqalunte(n) (LT1/164), a compound of alqa “swan” and lunte “ship”.