Keeping the Enemy at Bay

Ayren Cloudbreaker is at 48.5 25.3

You will fly on a predetermined path over 3 blood elf boats, activate the quest item to target the sails and to set them on fire. Your mount will then land on one of the boats allowing you to kill Belfs on them. The number of Belfs is limited, so you may need to swim to the other boats to get your kill quota. Conviniently the boats have outriggers that allow you to board them from the water. You can then retun to the island by way of the dragon hawk in the boat you land on, you wont be able to do this if you are in combat.

Upon recovering the Sun's Reach Harbor (completion of phase 3), this quest replaces Intercept the Reinforcements, and has the same objective but is a permanent daily quest that can be completed for reputation and reward, and will always be available once it is unlocked.

For more information regarding the Shattered Sun Offensive daily quests and the "phases" of reclamation, check out this guide on the Wowhead forums! :)