On multi-day trips in my tandem canoe, I use canoe portage packs that I line with waterproof Granite Gear eVent bags (no longer available). The bags are 100 D Syl-Nylon and have an eVent bottom that allows you to purge air:
With a lot of bilge water—for example in rain—water gets through the bottom and/or lower sides of the liner bag (the outer bag isn’t water proof to begin with). I kind of understand that with all the pressure from gear, the liner bag bottom gets pushed into a pool of water and it must be pretty difficult to keep it dry. I mean, it’s just treated nylon. BTW, I did recently seal all the seams.
Can a bag like this possibly work when pressed into a pool of water for hours? Are the clear plastic liners sold by Rutabaga, Duluth Pack, Frost River the only way? They’ve failed me at the seam before.
I remember Glenn McGrady used the same liner bags. It’s been a while since he last posted.