Camped this guy for 6 or 7 hours and not 1 spawn. A 53 bard and my 53 necro kept the whole boat clear no problem. We even tried just killing the scrubber and also tried clearing the docks but still no luck. The spawn rate on the captains seem to be totally random.
I just killed him. This captain was popped on the right corner of the triangle of mobs at the head of the ship. If you are facing the front of the ship, there is one mob at the very front then two mobs side by side a little further back. Cap. Taradon was on the right of those two. I arrived and he was there but if it is the same as Stormwave, then his PH would be the mob that is there when he isn't. Again, if it is like Storm then you only have to kill the PH.