The one major advantage of the karve I find is that it's easy to break down and carry through a portal. To break it down, stand at the mast and hit it with an ax until it breaks. If you are standing on the mast (and have room in your inventory), all of the components will go directly into your inventory without touching the water. So I keep a box at my longboat dock labeled 'Karve' with the exact materials needed to build one. Take it out of the box, carry it through a portal or to a friend's world, and then break it down and put it back when I'm done.