Hi Bob

> At what temperatures is it important to have a winter canister stove (i.e. canister upside
> down, feeding liquid), instead of a normal stove (canister upright) -- assuming normal altitudes
> (say sea level to 10,000')?
Many variables here. We have several good articles on winter use of canister stoves which go into this in some detail. Searching on my name and that of Will Rietveld will produce them.
Short answer: if the canister hits 0 C you will usually have problems. An iso-butane/propane mix can go lower.

> Do the upside-down ones have added safety issues, such as the possibility of enough liquid coming out to flare?
If the stove has a good preheat tube system, this is most unlikely. If it does not have a preheat system, it **WILL** flare.
A canister stove is identical to a white gas stove in this context, except that is is much safer because of boiling points of the fuels.

Cheers

Hi Steve

> the ease of pitching dome tents in adverse conditions
Maybe I was not clear enough here. I was focusing on those light 2-pole pop-up domes where the inner goes up and then the fly is thrown over. In a gale, these really are a problem. In fact, any of the domes with just 2 or 3 long poles are a pitching problem due to the wind cross-section.

When the dome has many crossing poles I usually call it a geodesic dome, as do many others. These are much stronger - but also much heavier. The Saivo has 7 poles! Very strong.

The first dome tent I ever made, in the early 60s, had two long internal poles. Yes, pitching it in bad weather was 'interesting'! Mind you, at 7' square it had a LOT of room. I think we managed to get about 12 people in it in the snow once for a birthday party...

> joy of winter camping
Yes!

Cheers

I agree with Roger that there is a lot of fuzzy thinking and vague terminology when it comes to dome tents. The North Face VE 25 is one of the standards on Everest and Denali (so I've been told, I'm not an expert) and it derives its strength from the self-reinforcing qualities of the geodesic dome. They say that Buckminster Fuller invented, or at least promoted this design, and it was used as the cover of our early detection radar in northern Canada and Alaska. You may have seen a few houses with all these triangular facets, which are derived from Bucky's geodesic mathematics. But the VE 25 and similar tents are very heavy, and not really usable as UL gear, at least until somebody uses titanium poles and Cuben sail cloth.

Actually, I have reservations about calling the 'geodesic dome tents' by that name. This is a REAL geodesic dome, Buckminster Fuller style.


We built that in the 60s on Mt Feathertop for the Melbourne University Mountaineering Club. It was designed on an IBM 7044 mainframe computer (cost 1 million pounds!) by a final year engineering student there. As he was one of the first to have ever done that design on a computer, he got job offers from international companies like Boeing.

The girl at the front is my wife.

EDIT: it occurs to me that many of you guys might be amused at what happened that first winter. We built the dome, locked basement, ground floor and first floor, in the summer. It was great in the summer.

But the first winter, with 20 bodies inside and damp clothes hung up to dry, guess what? Condensation on the inside of the aluminium shell! It RAINED! Oh Dear, oh dear!

We had to line the shell the next summer with decent thick insulation.

Cheers

Edited by rcaffin on 02/27/2009 21:03:35 MST.

Good article Roger and some interesting photos. Here's a couple from this winter in Scotland where we had some exceptionally heavy snowfalls. I had a couple of tents pitched during the snowy weather.





First is the TarpTent Scarp 1, second the Hilleberg Soulo. Both tents stood up to the snow fine.

Edited by Christownsend on 02/27/2009 16:09:19 MST.

Yikes Chris! That's pretty impressive!
I would love to hear more details about how the Scarp faired in these conditions!

Michael, the Scarp fared well. I used the cross poles of course. I think it would have collapsed without them. A couple of the connectors for the cross poles came undone in the snow and the inner did sag a little under them. It's possible I hadn't fastened them correctly as they are a bit fiddly with cold fingers.

I took the Scarp on an overnight trip up a local hill. There's a picture and report on my blog: http://www.christownsendoutdoors.co.uk/

Roger said:

>When the dome has many crossing poles I usually call it a
>geodesic dome, as do many others. These are much stronger -
>but also much heavier. The Saivo has 7 poles! Very strong.

Just to be clear, seven crossing points, created by four equal-length poles. Very strong (and, as you note, relatively heavy at 10 pounds).

Chris:

Fantastic pictures! Good to see both tents stood up to the snow loading so well. I tried the Saivo but found it too cramped, vestibule included, and so went with the Jannu for my smaller winter tent. Haven't regretted the extra weight yet for solo use, though I tend to use a pulk most times in the winter these days, not a pack, so that makes the weight easier to bear.

Two with winter gear can squeeze into the Jannu as well, which seems out of the question for the Saivo and Scarp (though I'll be curious to hear what you think).

Edited by slnsf on 02/27/2009 20:15:22 MST.

One thing I used to always take was a small homemade snow saw, about 18" long, like a small serrated sword with a wood handle. Didn't weigh much. With it I could cut medium-sized snow blocks for wind breaks or whatever.

In the old double A-frame days I'd make a wall of blocks around the tent entrance, up to the fly (about 16" up) which formed a covered triangular vestibule. It was outside the tent proper, but under the fly, and there was no CO2 problem cooking in there. Also no problem with spills. And I'd hang a candle lantern from the front guy that would light up the cooking vestibule and the tent.

Roger,

Thanks again for another great article. It seems timely to revive it again for the winter. I really appreciate your attention to detail in describing processes - the details are what keep me coming back to BPL.

I have a question regarding your comment on tent pole lengths - "shorter the better."

What has been your experience with the difference in stability between 2P, 3P, and 4P versions of 3 pole tunnel-tents (for example the Hilleberg Nallo 2 GT vs 3 GT vs 4 GT). I recently inherited a Helsport Rondane 4 and am wondering if the loss in stability/strength in the 4-man version will be appreciable - i.e. would two 2 person tunnels be a vastly superior option for 4 people due to the strength/stability advantages of the shorter pole lengths of the smaller tents?


Hope you are enjoying the holidays.


Cheers,
Brendan

Hi Brendan

First of all, I had better point out that I have not tested the Nallo tents (yet). However, I have tested short and long poles in other tents (tunnel and done and pop-up). There are two main points to look at here.

Using the Nallo as an example, you can see that going from a 2-man tent to a 4-man tunnel tent changes the biggest pole length from 305 cm to 368 cm: a 20% increase in length, and they are 9 mm poles. The biggest pole on the Helsport Rondane Light 3-man is 295 cm long. I couldn't find a Rondane 4.

Compare that with the 1-man Soulo (344 cm 9 mm) or 2-man Staika (387 cm 10 mm). Other small pop-ups and domes inevitably have similar long pole lengths as they have to span the length of a body.

So it would seem that tunnel tents always have shorter poles when you match tent sizes. That makes the poles very much stronger - the flex is a polynomial function of length. Translation: a small increase in pole length gives a much bigger decrease in strength.

The second factor worth looking at is how you pitch the tent relative to the wind. Pop-ups in particular do not have a 'good' direction, but tunnels do. Increasing the size of a tent is always going to reduce its strength, but the tunnel design does make about maximum use of the strength of the poles when the wind is end-on to the tent. Side-on - the poles on a tunnel are still shorter than the poles on other designs.

So the bottom line for me would be that the Rondane 4 is probably still pretty good as a mountain tent, although the fabric span between poles is a bit long. My suggestion is to try it out, with a couple of friends, and see how it goes. I suggest it would be a bit TOO big as a solo tent! Photos would be interesting.

Cheers

Thanks for your quick reply Roger,

I had the chance to read through your designs and thoughts on your MYOG tent website last night - (http://www.bushwalking.org.au/FAQ/DIY_RNCWinter.ht Definitely recommended for anyone that is interested in the finer points of mountain tent design). Thanks for posting that, it was a great read. Its quite an accomplishment to create something as smooth and efficient as your 4 pole 2-man design. I wish there was something commercially available that used a similar design and incorporated your CF poles (for those of us that are still refining the finer points of sewing summer bug inner tents : ) ).


Below is a link to the last available Helsport Rondane 4 that I could find online - I believe that sometime after 2005 (mine is a 2005 model) Helsport changed styles and stopped producing the Rondane 4. The website has the basic floorplan/fly diagrams as well as the picture that is embedded below.

http://www.reittipiste.fi/product_info.php?manufacturers_id=70&products_id=692&language=en

Additional information on the original Rondane line-up:

Rondane 3 Packed weight w/o stakes: 2.2kg, 1 pole x 295cm, 2 poles x 220 cm
Rondane 4 Packed weight + guylines w/o stakes : 2.79kg (measured for mine with heavy stock guylines), 1 pole x 347 cm, 2 poles x 270 cm

Fly material (both): Superlight 1000 Ripstop Nylon
Pole material: Scandium Superpoles (34cm sections)

Its a bit hard to see in the picture but the fly has quite a large vent on the side opposite the door that is supported by stiff foam and is approx. a half circle of 30cm diameter.

I hope all's well down your way and you aren't getting hit by the brunt of the storms down there (my family out in Queensland have sent some amazing pictures of the flooding/highway waterfalls).

Cheers mate,
Brendan

Edited by dools009 on 12/28/2010 08:44:24 MST.