From WoWWiki

The Sin'loren is a blood elf destroyer in the waters north of the Sun's Reach Harbor, Isle of Quel'Danas. She is the southernmost ship of the fleet.

This ship is one of three containing Dawnblade blood elves, as reinforcements for Kael's forces on the Isle of Quel'Danas.

This is also the ship you land on with your dragonhawk to slay the elves, after having set the sails ablaze preventing them from getting to their destination.

Patch changes

Patch 2.4.0 (3/25/08): Added

Subzones of the Isle of Quel'Danas
The Bloodoath • The Dawnchaser • The Dawning Square • Dawnstar Village • The Dead Scar • The Forbidding Sea • The Great Sea • Greengill Coast • Magisters' Terrace • Shattered Sun Staging Area • Silvermoon's Pride • The Sin'loren • Sunwell Plateau • Sun's Reach • Sun's Reach Armory • Sun's Reach Harbor • Sun's Reach Sanctum