To begin the quest, go to the Dancing Peacock and accept the quest from Kirtada. "That request is from a vessel. It says it wants the champion of the alliance with the Vessels to fetch something. It specifically requests ice that can be found in the Underground Lake. Could you take on this duty? Oh, you'll need this. It's a leather bag designed to keep ice frozen for six hours. Perhaps if you are successful with this request, it will improve Tharsis' standing in the eyes of the Vessels. Try not to make too many mistakes where they are concerned, [your guild name] Guild."