Never leave your boat on shore. Crash it and store mats in chest. This is one of this game's basic lessons. In this game, you die two or three times in zones where enemies still strong for you and like dozen times in places where's nothing to fear... because you lose concentration. One glorious death vs ten stupid deathes, that's how it works.

I also prefer to use carve, not longboat, since it easier to navigate and easier to carry in backback.