Single-skin or flysheet?

Al Downie said:

Could you do a short essay please on the relative merits and demerits of
conventional tents and those new fangled Outdoor Designs single-skin
Goretex jobs? The panel will look favourably upon good spelling and
references to condensation.

Goretex (or other single skin) tents tend to suffer more from
condensation problems. Even with strides in breathability over the
years it's still the case that it's easy enough to come against the
limits of Goretex breathability, and that's with the vapour pressure
being created right next to the laminate. Put it a few feet away in a
tent in a humid climate and you're asking a lot of it for the vapour to
get pushed through.
Also the case that without an area of relatively still air between fly
and inner the insulation value of the tent will be less, so you'll cook
more in summer and freeze more in winter. Other problems of single skin
tents is they tend to have rather teensy porches.

All of the above points to a trad double skin probably being rather
better for typical UK conditions of high humidity and frequent rain.
And it's not that surprising that the main market for single skin tents
is high altitude mountaineering, where humidity isn't so much of an
issue and light weight, small footprint and bombproofing takes
precedence. So if you've decided to do a big peak in the Andes or
Himalayas then one of the single skin ones would probably be just the
ticket, but at home I'd look at double skins with good size porches.
Note that Terra Nova have been making single skin tents for years, but
don't really market them much outside of expedition altitude use. To
quote their web page on the Gemini Goretex model,

"The Gemini, designed for high altitude mountain and polar expeditions
where the air is cold and dry, has been extensively tested in the
Himalayas and Karakorum. It is quick to pitch, and has a minimal
footprint making it ideal where space is limited.

Please note: the Gemini has been specifically designed for use in cold,
dry environments. Its performance will be severely inhibited if used in
other conditions."

I'd think if single skin tents were much good outside of these areas
they'd have a stronger representation in the market. As it is, they
appear every couple of years in a slightly new guise, get talked up, and
then disappear back to their specialist niches again.

A twin skin that will still work well up a mountain (not too heavy but
will take a major bashing and will go on marginal pitches) would be the
Crux X2, which is quite a bit lighter than an Ultra Quasar or similar.
If you're not so interested in a need to stand up to howling gales on
ledges then there's plenty of choice, but the general case is out of
big, light and strong you can have any 2...

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

Steve said:

My understanding of the state of play with double skin tents, contrary
to what might be immediately thought, is that condensation is quite an
issue...

This is indeed the case, but All Things Are Relative. In a twin skin
with a double coated fly (inside and out) that goes down to the ground
you'll get /loads/ of condensation on the inside of the fly. But you
shouldn't get anything in the inner, aside from possibly something on
the floor.
Inners are best lightly proofed, to deal with any drips that come off
the inside of the fly onto the inner (i.e., after you've tripped over a
guyline during a pee break in the night), but if that's done then the
inner should stay dry.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

Thanks all,

I'd seen the Gemini page on Terra Nova's site, and I'd heard all the
stories about the condensation/temperature problems, but the new
(fangled) Outdoor Designs tent has a different type of Goretex membrane,
which is supposed to be much more breathable and therefore less prone to
condensation. I'm a bit skeptical though, and will probably wait till
it's been tried & tested.

Interesting to note too that the Gemini is available for ?330, as
opposed to ?450 for the OD tent. I'm a big fan of Terra Nova - my Quasar
is great, but just a bit of a faff on a dark, wet & windy night.

Cheers,

Al

Al Downie said:

I'd seen the Gemini page on Terra Nova's site, and I'd heard all the
stories about the condensation/temperature problems, but the new
(fangled) Outdoor Designs tent has a different type of Goretex membrane,
which is supposed to be much more breathable and therefore less prone to
condensation.

Gore keep on improving their products, but I'd guess they've still got a
long way to go before they're anything like as breathable as the
marketing often suggests... I've not personally spent a night in an
Exchange Goretex tent, but I note that even OD don't seem to be
suggesting their tents are Really Quite The Thing for general UK
camping, with all the tents seemingly aimed at quite specific niches.

Quoted message said:

Interesting to note too that the Gemini is available for ?330, as
opposed to ?450 for the OD tent. I'm a big fan of Terra Nova - my Quasar
is great, but just a bit of a faff on a dark, wet & windy night.

Where the OD single skin will probably just be a different sort of faff:
nowhere much to put your gear and the rain blows straight in if you open
the door (unless you want to blow £700 on a "ProjectX"😉. For a quick
pitch on a wet windy night then something which pitches either outer
first or both together is a lot more convenient than a Quasar, where you
have to sort out two different lengths of pole and thread them through
the inner's sleeves while trying to keep it dry. One of Hilleberg's
tunnels should be a lot easier on a cack night and will take most winds
you're likely to find outside of really exposed pitches, and you'll
still have the Quasar for that. The tunnel would be a lot lighter, and
probably have quite a bit more room too, might as well look into
something that'll do stuff the Quasar won't (give you more room at lower
weight in the case of something like a Keron 2).

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/