When I made a tarp from 4oz nylon I found the nylon difficult to hold in position, whilst sewing the seam tended to slip apart. I used some glue to hold it together and then sewed it. However the glue tended to jam the needle so I would suggest using smal dots of glue to tack in place. I think the best seam is a flat felled seam and proof the seam when finished using silicone.
The zeltbahn has fascinated me ever since I saw a German Scout Black tent. Which is similar in that it is a modular canvas affair that can be joined together with others to make tents of one, two, four, six or eight sheets. The eight sheet size being bigger than an English scout patrol tent. As each person carries a small part of the whole tent it becomes very easily transportable. The zeltbahn also has the function of a poncho. I don't have one myself but I do have a Norwegian shelter sheet which is losenge shaped rather than triangular and is made of a substantial canvas material . I think that the weight of canvas helps its function as a poncho as the weight helps it to stay put and not blow away. As a shelter I think a very lightweight nylon may need extra guys to hold it in place and stop it flapping. Are you think of making several so that they can be joined together to make a larger tent?. You would have to be accurate with the design, sewing and button holes although with modern materials it might be possible to use a press studs and velcro rather than buttons. I think a shelter sheet/poncho that can be joined together to make a larger tent would be an excellent thing to try for groups of Scouts or Cadets or for DofE expeditions.
It will be interesting to see when finished, keep us all informed.
NickP
