Re: Water bottles or bladders?

The Cairn was designed by Don Whillans, Tom Patey, or someone else in that crowd, made in England. In those days, you didn't see the huge logos like you do now, so I'm not sure who actually made them at this point. If it were to be made these days, you would use more modern fabrics.

Basically, it is a lot like some of the summit packs, but about 2700-2900 cu in in a heavy canvas fabric (substitute cordura these days). Like many summit packs, it is a single, load from the top compartment with a top flap pocket. And here is where it starts departing - leather bottom, inner fold-out liner to form a lower body bivy sack, crampon straps on top, ice tool loops with tie-downs for the tools, haul rings (can be used as a pretty durable haul sack of the "rapid alpine ascent" size), side attachments for skis. Typical of the Clogy/Scottish Ice rucksacks, it has heavy straps with leather ends and metal buckles.

Combined with a cagoule and a down parka with wool clothes, the sack is intended for bivying in a Scottish ice storm. These days, substitute synthetic cordura-type cloth for the body and foldout, both with a heavy durable coating to be fully waterproof, one of the modern plastics or webbing for the attachment loops for the ice tools, skis, and crampons.

My Lowe Alpine Attack 40 and my Lowe South Peak Centro 40 have some similarities, but are smaller and do not have the foldout for the bivy foot-sack. One nice thing the Alpine Attack 40 has that would be nice for a modernized Cairn is that it has a folded closed cell foam pad that acts as a frame, and when removed can be used as a pad to sit on when bivying or as a splint for an injured limb (BD had a summit pack with the same idea).

The main thing that the Cairn has that I haven't seen in current packs is how it all works together to do the job of a pack for alpine-style ascents with a possibility of getting caught in a storm. In other words, much more multipurpose with what you need but nothing extra, and unlike many pretenders to the multi-purpose gear item, it really does all it is intended for quite well.