If you are already hypothermic and have nothing but a string in your pocket, I would think that your survival is hanging by a thread and you are probably SOL.
That is, unless your non-hypothermic hiking partner can build you a fire or warm you up somehow ASAP. Because a hypothermic person is in no condition to act quickly and decisively, even if they have far better resources at hand than one piece of string.
I agree.
Building a fire with a bow drill is not an easy task in the best scenario (manufactured equipment and plenty of dried tinder). I've never seen anyone build a fire with an improvised bow drill in any reasonable amount of time. I've never seen anyone do it period when its cold and wet outside. It is a fun exercise to help you appreciate modern society and maybe a useful skill for a post-apocalyptic society, but I would not consider it a reasonable survival skill.
The OP did mention using a sparkler for the no matches, no lighter fire building technique. The problem I have with that, is that I could have three more lighters for the weight of a sparkler. Any failed equipment scenario where I have a sparkler I can think of, I would be better off with extra lighters/matches. Lighting a fire with a sparkler is a real challenge. The OP also mentions a magnifying glass. If I am cold and wet, is the sun out? I think I would rather bring an additional lighter with me than a magnifying glass.
Building a fire WITH a match or lighter in a challenging environment is a skill I think people should practice. It is something I failed at after a heavy rainstorm while backpacking outside Phoenix. Alas, it can be challenging to find yourself in that situation with proper planning.
Previous Topic
Index
