If we wish to stay the executioner's axe, we'll need to throw Sylvanas off of our scent. I will take the ship near Chandlery Wharf, which has recently been taken by Irontide pirates. There, I will leave it under the guise of a pirate raid gone wrong.
Your task will be to ensure that Sylvanas' forces find this ship.
You must report to Nathanos that you spotted a stolen Forsaken vessel in that area. You have no connection to Derek Proudmoore, so it should raise no suspicions.