Seriously Converting to Multiuse Only, help required
So first off, I finally have some time to talk after being away from the forums for a while. Welcome, welcome, yes, yes *shakes hands* *kisses babies*
Short history: After looking at my pack and all items within, I managed to get it down to a scant 10lbs including 6lb sleeping bag (it was a freebie down, how could I not take it?), 5L worth of water reservoirs/bottles, mess kit, emergency tin, health kit, and tent. Yay me! Backpack itself still weighs a horrific 5lbs but I can handle it. After reading up on some backcountry experiences locally, I realized I never did a water crossing but they say it's as easy as wrapping your pack in your tarp, tying it off, and using it as a flotation device. Now, don't knock this idea like the whole "I'm going into the Canadian bush for 3 months with just a knife" idea. This guy actually knows what he's doing. Aside from skepticism, I would really enjoy the possibility of expedient water crossing next time I come to a river or lake narrow. But because the bugs in upper Michigan are as bad as they are up in Alaska post-thaw (I blame our millions of miles of cedar swamps), I'm not switching from my bug-proof tarp tent (already only 1.5lbs) to a sheet tarp which I can use to wrap my pack.
The idea: I have a small 3x6' section of Tyvek housewrap that i use as a groundcloth every now and then. It's lightweight (about 100-150g), rip-proof (have you every tried to rip tyvek? it's bombproof!) and waterproof (so they say) so why not use it instead of a tarp? I can get a large sheet approximately 6x8' for $14 and can use it folded as a groundcloth, attach grommets to the corners for a poncho shelter (when the bugs aren't bad), and (if it is waterproof) I can use it to wrap my pack for crossing water. Not a bad idea if it works.
The problem: Is Tyvek housewrap waterproof? Waterproof is a relative term. Waterproof on a house could mean "sheds water". Waterproof while floating in a fricken lake HAS TO MEAN "water will not penetrate membrane".
