Having seen mention of this on the Furtech site, I'm delighted to see a nice photo here and a lot more detail has been added to the shellta wordpress page since I looked last week.
I've been looking at similar things from the US & Canadian lightweight manufacturers (Integral Designs, Six Moon Designs, Mountain Laurel Designs etc.) but 1) they are hard to come by in the UK and 2) I don't think any of them claim to be capable of 'all of the above'.
That said, it's a membrane so a bit on the heavy side compared with silnylon - and certainly heavy compared with some of the Cuben spinnaker stuff available in the US. But that makes it a more appealing bivvy bag so I suppose you pays your money and...
Either way, it's an interesting take on the problem of carrying versatile shelter and as before I wish Andy great success with it.
I'd have a few questions to pose here if Andy was as open & helpful as he was about his Furtech jackets.
1) Hydrostatic head? Is there a risk of squeezing water through the membrane if it's against the ground?
2) Drying time. If it's hydrophilic, and presumably the face fabric can eventually wet-out, does it take a while to dry?
3) Does it need any special care to keep the membrane functional - as would be the case for Goretex or Event
4) As the fabric isn't gas permeable, is the bivvy bag mainly an emergency / under-shelter use option
5) Is there any risk of damaging/delaminating the membrane if it is stretched out between guy points?
I have to admit to being a bit skeptical about whether the hydrophilic nature is sufficient to 'dry out' a Nikwax analogy fabric. I do believe, however, that wearing a waterproof poncho over any breathable waterproof jacket will up the breathability for a few reasons. Firstly, there's some airspace for the surface moisture to evaporate off; secondly there might be a slight warming of the gap between poncho and jacket so the vapour transmission of most membranes would improve (the r.h. should fall on the outside of the jacket so permeability should rise in most cases).
John
Posted: 31/10/2008 at 17:36
