Re: The NEW Ten Essentials

I think they are referring to any type of shelter that could be used in worst case scenario. I would count the hammock as a primary shelter and a survival shelter only in some situations. If you are hiking an area without trees it will be alot harder to use the hammock. However since you mention tarp, i would count that as a survival shelter because it is light enough to pack it without weighing it down much and you can use a tarp almost anywhere.