Puckster wrote on Dec 8^th, 2012 at 4:48pm:

Interesting discussion.  Are the Ostrom packs waterproof, or do they require plastic liners?  I'm curious why no one commented on the waterproof genre of canoe packs, like the North49 Waterproof Canoe Pack 120 L.  I have no experience with these "rubber" packs, but the waterproof nature of them is, on the surface, appealing.  They do look bulky and uncomfortable, but again, I have no firsthand experience.  prouboy

Ostrom packs aren't waterproof, at least mine isn't. I use GG liners, plus my clothes, food, sleeping bags and shoes are all in waterproof bags as well.
I have never used a water proof pack but the problem may be that given rough use and abrasion, they won't be water proof for long.
As for using a tump line, from a physiological point of view I couldn't say.  But keep in mind that I'm not using an old Duluth style pack where all the weight is ending up on my neck.  My Ostrom is well fitted with a hip belt.  I just find that the tump helps to distribute the weight and makes carrying a heavy pack (around 80 pounds -  I'm typically out for 3 weeks at a time) a whole lot easier ... for me, that is.