Forum Index » Editor's Roundtable » Storm Resistance of Ultralight Shelters: Part 1, Introduction


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Rakesh Malik
(Tamerlin)

Locale: Cascadia
Re: is still a "failure" on 02/01/2012 12:45:11 MST Print View

I'm glad you guys are doing this review, because I'd love to be able to save weight yet still have a shelter that's up to handling extreme conditions. :)

Craig Rowland
(craigr) - MLife

Locale: Pacific NW
Sweden on 02/01/2012 13:18:09 MST Print View

On a trip to Sweden this summer I had a chance to meet Bo and Renate Hilleberg. They were wonderful people and gave me a tour of their tent design headquarters in Ostersund, Sweden.

They test all tents in front of a custom designed snow blowing machine. Their four season tents are tested up to 30 m/s (67MPH) if I recall. Not just tested for strength, but they have employees go out in the wind and setup the tents to simulate storm conditions. They feel it's important for a tent to not just be strong in a storm, but able to be setup quickly in bad conditions.

Bo Hilleberg is well aware of the lighter materials available on the market, but after testing many of them they have chosen not to use them. They are not strong enough to survive northern Sweden winter conditions and feel that shelter safety is compromised. As a side note, they also state that materials with fire retardants added to them significantly weaken the tear strength. In their testing they state that adding a fire retardant can reduce tear strength by up to 90% in common tent making materials.

I love my Hilleberg Akto. Probably not the best for heavy snow loads, but in a storm it's a very strong tent. For 3.5lbs it's really hard to beat.

Thanks for your interesting and comprehensive review. Very well done.

Edited by craigr on 02/01/2012 13:20:39 MST.

. .
(biointegra) - MLife

Locale: Puget Sound
Re: Storm Resistance of Ultralight Shelters: Part 1, Introduction on 02/01/2012 14:05:47 MST Print View

This is BPL!

Rakesh Malik
(Tamerlin)

Locale: Cascadia
Re: Re: Storm Resistance of Ultralight Shelters: Part 1, Introduction on 02/01/2012 14:30:05 MST Print View

> This is BPL!

So you're saying that part of being ultralight is to either face the storm like a man, or stay home in bad weather? ;)

Craig Rowland
(craigr) - MLife

Locale: Pacific NW
Re: Re: Storm Resistance of Ultralight Shelters: Part 1, Introduction on 02/01/2012 14:38:05 MST Print View

> This is BPL!

The Akto is light when you consider it is designed to work in winter storm conditions reliably.

I'm not ashamed to admit I carry the Akto most of the year. My base weight with the Akto is 15-20lbs and I sleep like a baby during storms.

Rakesh Malik
(Tamerlin)

Locale: Cascadia
Re: Re: Re: Storm Resistance of Ultralight Shelters: Part 1, Introduction on 02/01/2012 14:52:57 MST Print View

> The Akto is light when you consider it is designed to work in winter storm conditions
> reliably.

That's also why I picked up a Twin Sisters. Well, that plus it was on clearance at REI. :)

Dave U
(FamilyGuy) - F

Locale: Rockies
Re: Re: Re: Storm Resistance of Ultralight Shelters: Part 1, Introduction on 02/01/2012 14:54:41 MST Print View

"The Akto is light when you consider it is designed to work in winter storm conditions reliably."

But poorly designed for the conditions that you suggest. The tent cannot withstand very much snow load. In terms of design, the Scarp had surpassed it in every way. As such, it really isn't that 'light' for winter storm conditions.

FWIW, I have used a Duomid and an Akto in high alpine, snowy conditions. The former withstood the conditions much better and we don't have to discuss the weight differential (or price differential).

Craig Rowland
(craigr) - MLife

Locale: Pacific NW
Re: Re: Re: Re: Storm Resistance of Ultralight Shelters: Part 1, Introduction on 02/01/2012 15:07:04 MST Print View

The Akto is not designed for heavy snow loads it is true. But it is used routinely in arctic conditions anyway by some. They have tunnel tents that are larger for slightly more weight but better snow load handling.

I've looked at the Scarp and it looks OK. I've looked at the pyramid type shelters in the past. I got turned off from them after a couple stories from people I know discussing the failures they had.

Edited by craigr on 02/01/2012 15:10:09 MST.

Nick Gatel
(ngatel) - MLife

Locale: Southern California
Re: Re: Re: Re: Re: Storm Resistance of Ultralight Shelters: Part 1, Introduction on 02/01/2012 15:09:49 MST Print View

I think the Scarp is double-walled, mine is.

Craig Rowland
(craigr) - MLife

Locale: Pacific NW
Re: Re: Re: Re: Re: Re: Storm Resistance of Ultralight Shelters: Part 1, Introduction on 02/01/2012 15:10:40 MST Print View

Yeah I confused it with another tent and edited my post.

Sam Haraldson
(sharalds) - MLife

Locale: Gallatin Range
Storm Resistance of Ultralight Shelters: Part 1, Introduction on 02/01/2012 22:07:33 MST Print View

I predict the "winner" to be the Black Diamond Mega Light.

eric chan
(bearbreeder) - F - M
no pulls on 02/01/2012 23:01:32 MST Print View

i look forward to the pull no punches testing to come ...

it doesnt matter whether they are sacred cottage cows ... or hated mainstream demons ... just call the results as it is ... thats all i ask of BPL

ultimately what makes it valuable for me is for BPL to test and indicate the most survivable shelters for the conditions at hand ...

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: is still a "failure" on 02/02/2012 03:38:31 MST Print View

Hi Peter

> if i pre-bend my poles, in a situation where the mfg expects the rear pole to be installed
> with a ridiculous** amount of bending .. does this make the pole ultimately stronger (as i
> suspect) or weaker, considering it gets hit with equal loadings.
Not simple.
* A tighter bend does put more stress into the arch and that makes it stiffer, which is good.
* But a tighter bend leaves you with less safety margin, so it would be easier to break.
* In addition, with some poles, repeatedly bending the pole too much 'work hardens' it, which makes it more brittle, and leaves it very susceptible to abrupt failure. The Easton 7178 poles suffered from this problem, and snapped on me.

Cheers

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: use of shockcord on 02/02/2012 03:41:15 MST Print View

Hi Michael

> This series might have me re-think using shockcord loops for my LDPE shelters.
There's shock-cord, and there's shock-cord. I used 100 mm long loops of 4.5 mm shock-cord on the down-wind end of my winter tunnel tent to apply the lengthwise tension. But I use loops of 3 mm nylon on the upwind end: I do not want that end moving!

Cheers

Hamish McHamish
(El_Canyon) - M

Locale: USA
_ on 02/02/2012 13:39:46 MST Print View

Great article, looking forward to this line of inquiry.

Already, I can see justification for MLD's approach to using cuben. Not every Joe Blow working out of their garage is properly designing and manufacturing their cuben products.

John Coyle
(Bigsac)

Locale: NorCal
Storm Resistance on 02/02/2012 14:24:12 MST Print View

I truly welcome this series of articles because wind worthiness, and to a lesser extent snow loading in tents has always been a pet peeve of mine.

It would be nice if tents were rated with a W factor (for wind) much like sleeping pads and air mattresses are rated with an R factor for warmth. Of course manufacturers could still fudge the rating, but places like BPL could keep them honest.

For example, I have a SMD Sil-Nylon Trekker which I bought last Fall. It seems fairly wind worthy, but I haven't had it in winds over 15 MPH, so I really don't know how it would stand up to sustained 30 MPH winds.

It's funny because a friend of mine recently bought a Hilleberg Akto and I kid him about his "over engineered heavy Swedish monstrosity" But I have to admit, with 10 stakes, and each stake attached to the tent at two points, I believe it is bombproof in the wind department. This youtube of an Akto in 80 MPH winds would back up my opinion. http://www.youtube.com/watch?v=a1iJvk6tKs4

Stuart Murphy
(stu_m) - MLife
Re: Storm Resistance of Ultralight Shelters: Part 1, Introduction on 02/03/2012 00:00:45 MST Print View

I do hope even if wind machines don't become part of the test process that video is part of the data available to readers. Survivability is one thing, live-ability quite another. Some tents flap more than others and all things being equal may be less live-able in some conditions.

A wind/snow rating should also take into account whether the structure can function in the conditions for a protracted period (a tent surviving a storm for an hour is different from it being routinely able to withstand such conditions without damage).

Another important factor is pitching/striking camp in those conditions (when a tent is at its weakest and seriously at risk of bent poles etc) as per the person that posted about Hilleberg's testing, so there should be video of that too.

Come on BPL, buy a wind machine... you know you want to.

http://www.youtube.com/watch?v=kLligRPO4tU

Edited by stu_m on 02/03/2012 00:07:26 MST.

Adam Kilpatrick
(oysters) - MLife

Locale: South Australia
Re: Re: Re: use of shockcord on 02/03/2012 04:04:50 MST Print View

"There's shock-cord, and there's shock-cord. I used 100 mm long loops of 4.5 mm shock-cord on the down-wind end of my winter tunnel tent to apply the lengthwise tension. But I use loops of 3 mm nylon on the upwind end: I do not want that end moving!"

I've done something similar with my trailstar, putting shockcord loops about that big on three of the main corners that go into the wind, the other two I've got guyline on. It works well. I'll do it in the future with other tents and tarps. Having that bit of gust resistance is valuable in protecting your stake outs.

:-)

Diplomatic Mike
(MikefaeDundee)

Locale: Under a bush in Scotland
Shock cord on 02/03/2012 09:13:49 MST Print View

I use shock-cord on mid-panel tie-outs, but not on main guying points. Especially not the ones into the wind!
I also use it on the tie-outs of bivvys made from UL materials.

kevin timm
(ktimm) - M

Locale: Colorado (SeekOutside)
Shockcord / snow loads on 02/03/2012 09:44:28 MST Print View

It has it's advantages, as it tightens a panel over time, so it can keep the tent pitched tighter. The key, is to find shockcord of the appropriate tension for your tent, and to pull it tight or extremely near tight, so there is little give , but much more take. IMO it really works better on non seam tie outs, as seam tie outs have the stretch limited anyway.

Snowloads are extremely difficult to mimic, as almost every snow is different. I live in an area where we get substantial (250 + inches some years) snow, and I test a lot of single pole tents and tipi's to determine failure.

Yesterday and last night it snowed, but it was the type of snow that started wet, so without maintaining it , it would stay on the canopy. I let the snow accumulate over night, then measured the carbon fiber center pole deflection (very minimal), brushed the snow off the tent, then put the snow in containers and weighed it , to get an idea what weight was on the canopy. The weight on the canopy from the snow, was close to 120 lbs accumulated on the canopy, in fact probably more if I take residual ice into account.

The best way to minimize snow load on center pole mid / tipi type structure is to have a place for the snow to go, like a trench if snow camping, or a short sod skirt style mini wall