While staying in a forest service cabin on POW island a couple of years ago I ran into 2 kayakers from Germany. They were out for 3 weeks and circled the island from Ketchikan. They said they barely made it past the southern tip due to currents and at one point were not sure they would. They had sit in ocean kayaks with full skirts and seemed pretty experienced.
As others have mentioned, no browns on the island but you will see some blacks. I dont think you need the heavy artillery, bear spray should be fine IMO.