The whole point of this exercise is to put our heads together and see if we can find a good method of boiling water with only a knife and firemaking tools. Lots of good ideas so far. I think as it stands, Chris' idea is in the lead though based on the primitive pottery tutorial I read yesterday at BCUK, it would probably require every second of the 8 hour time limit. I'm hoping to have time to try this on Sunday so if I do I will let you guys know how well it works and how long it takes. I'm thinking it will take me 1 hour to construct a good container for boiling then it's about 4 hours minimum firing time (hopefully not more). That leaves 3 hours to cool the pot a little and fill it with water (that I will probably strain through a t-shirt) then boil and cool that water for drinking (maybe another hour?).

So... if it takes 1 hour to make the pot and 1 hour to boil and cool a liter of water then I have 6 hours to fire and cool the pot. The earthenware pottery tutorial that made the most sense to me (there are many such tutorials at BCUK and I didnt read them all) suggests firing your pot in a "huge" fire for 3 hours then letting the fire die out naturally and letting the pot continue to sit in the coals overnight as the fire/coals dies/die out naturally. This obviously has to be modified to meet the 8 hour time limit. Also the author of this tutorial states clearly that although the resulting pot will hold water, it will also sweat as well which is why I am suspecting that boiling a liter of water may take a little longer than it would in a completely waterproof container.