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Cuben Tent Question?
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Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Cuben Tent on 12/21/2009 14:16:52 MST Print View

Hi Lawson

With ventilation at each end, yep. A bit like this in fact:

ColDePalet4119
Col de Palet in France.

> The tent would cost you an arm and a leg.
Yeah, about $1,000. At $3/hr for the labour.

But as I said just above, with a judicious blend of fabrics it just might be possible. Hum .....

Cheers

Edited by rcaffin on 12/21/2009 14:17:30 MST.

Miguel Arboleda
(butuki) - MLife

Locale: Kanto Plain, Japan
Re: cuben tents on 12/21/2009 15:54:09 MST Print View

Rpger, thanks for the information about how tent sleeves and such work. As someone who has made his own tents and tarps it is very educational. SO much to learn!

How about these two ideas from two tent designers here in Japan:

Arai Tents. Take a look at the way the tension is spread out in the sleeve.

Nippin Messner Tents. These tents use a continuous cord to attach to points on the seams. Probably has the same problems as clips though.

Edited by butuki on 12/21/2009 15:55:48 MST.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: cuben tents on 12/21/2009 18:52:59 MST Print View

Hi Miguel

At the top of the Arai page there are two diagrams of poles in sleeves. One has the sleeve very wide at the base - I don't see that idea being of much use - in fact I strongly dislike it (pending a better explanation of what it means!). The diagram on the right shows the sleeve coming together where it joins the tent. That is the method I use. I make the sleeve about 20 - 25 mm high (seam to pole centre). The sleeve securely locates the pole wrt the tent, and distributes the tension uniformly. Definitely snow tents, not for rainy weather.

The Nippin Messner design - it's a cheap consumer pop-up. The cord system ... kinda cute, but heavier than a sleeve. I wouldn't want to be trying to get it erected safely in a storm though. Strong risk of ripping out some of the point attachments. Too much stress concentration. But it probably wasn't made for that anyhow.

Pity I can't read Japanese ... :-)

Cheers and thanks

George Geist
(geist) - M

Locale: Smoky Mountains
Re: cuben tent on 12/21/2009 19:14:10 MST Print View

> the tent might just be dynamic enough to be a 4 season cuben fiber tent
> ...would have to use at least the .75oz and as you said tape the seams

I curious to learn from folks who have Cuben shelters where have you seen the Cuben fail because that helps determine what (weight/type) of Cuben it takes to stand up in a storm tent. All I've heard about are tears around the tie-out points. That could be remedied by learning how to better reinforce this type of material rather than simply using heavier material in the bulk. On the other hand if folks have experience with the really light Cuben failing out in the middle, then that is a good reason to use the heavier versions in the bulk.

I've also heard about folks being able to tear the edge of the lightest Cuben, but can you tear a finished edge? Because that is what is going to be on the tent.

Lawson Kline
(Mountainfitter) - M

Locale: LawsonEquipment.com
cuben tent on 12/21/2009 20:02:13 MST Print View

Hey Al,

The CT1K.08 17.4GM2(.50oz)Cuben has similar break strength(68 lbs/in) to most silnylon at (70 lbs/in).

I talked to the folks at Cuben Tech the other day and they said they have never done any tear testing but they feel it would be similar to silnylon which ranges from 8-16 lbs/in depending on the type of nylon (nylon 6 or nylon 6,6) and coating method along with weight.

I think it would make more sense to use the CT2K.08 25.4 GM2(.75oz) Cuben since it's similar in cost but it's load @ 1% strain is 50% more (24 lbs/in vs.35 lbs/in)and it's break strength is 55% more at 105 lbs/in.

But then again as you said, if you properly seam the material and add extra support at critical area's why not use the lighter material especially if it's on par with silnylon. If the shelter took 6-8 yards of cuben you would save roughly 3-4 onces by going with the lighter stuff.

Lawson Kline
(Mountainfitter) - M

Locale: LawsonEquipment.com
cuben tent on 12/21/2009 20:10:43 MST Print View

Ross,

Sorry I didn't address your comment earlier. Good idea on the 2 person design using both parties trekking poles. If you go alone you can bring poles for the rear.

I was thinking of going with a front width around 54" and a back width around 40" and a front height of 42" and a back height around 30". What do you think?

Samuel C. Farrington
(scfhome) - M

Locale: Chocorua NH, USA
cuben tents on 12/21/2009 22:58:43 MST Print View

1. There was a tunnel tent, maybe a Kelty, that used a triangular panel on the roof, with a corner top dead center on one of the hoops, and the base of the triangle centered on the top of the other hoop. The apparent purpose was to max the tautness and catenary cut with the fabrics used. But it might be a thought with cuben, which could also serve as a translucent skylight. But you would want the straight grain edge of the nylon attached to the cuben, so that the fabrics wouldn't have different coefficients of expansion where joined, which would create all kinds of problems. So it would have to be at or close to a right triangle, with the right angle at the TDC vertice. (Note: Nylon fabric only stretches very much on the bias (diagonally to the weave. There was some discussion of this in the current BPL article about the Montbell spiral wrap bag.)
Also seem to recall a 3 or 4 pole hoop tent by Early Winters that used seams parallel to and between the hoops to obtain a taut catenary pitch. They had one made of Goretex laminate, which did not stretch much due to its thicker lamination, and maybe that's why they had to add the seams between the hoops.

2. I don't think crossed hiking poles really create enough space to replace a hoop at the high point of the tent. Maybe at the lower end, or maybe using just one pole to support an awning that could also be rolled up for high winds.

3. Agree that sleeves and internal poles are stronger than clips, all other things being equal. Sleeves do contribute significant weight, however. The trick is to figure a way to get the internal poles installed and stablized without having to crawl into at least part of the tent.

4. Looking at the above tents and designs, am tempted to put on a flack vest and sunglasses, visit Warmlite in Gilford NH, and ask them if they could make a their 3 hoop model 3 mostly out of cuben supplied by the customer. If I survived to tell the story, the response would be interesting.

Thank you for the Japanese links. Especially liked the video of the wedge being pitched in real time.
Sam Farrington, Chocourua NH

Edited by scfhome on 12/21/2009 23:03:43 MST.

Miguel Arboleda
(butuki) - MLife

Locale: Kanto Plain, Japan
Re: cuben tents on 12/21/2009 23:18:34 MST Print View

The Nippin Messner design - it's a cheap consumer pop-up

Hmm... well... those are top-of-the-line mountaineering tents designed in collaboration with Messner himself (hence the name, though that doesn't necessarily mean the tents are good!). The tents come in at around $600~ $700 and are not meant for the average consumer's use. I've never used one myself, but a mate of mine hikes in one all the time and they are his favorite mountaineering tents.

I've been pondering the issue of clips versus sleeves and wonder why clips are considered inferior? We use tremendous force on guylines, much greater than on roof panel sleeves, which normally pull at only one point, and yet also require the load to be as spread out as much as possible. Why should clips be any different that way?

My Soulo uses both sleeves and clips and the clips are mighty strong. The tent (not mine) has proved itself in extremely harsh environments. Don't clips also relieve some of the stress by not acting as wind-catches?

Edit: I meant to write, "A mate of mine hikes with one all the time... be kind of interesting watching someone hike in a tent!

Edited by butuki on 12/22/2009 00:08:23 MST.

Samuel C. Farrington
(scfhome) - M

Locale: Chocorua NH, USA
cuben tents on 12/21/2009 23:54:30 MST Print View

Miguel,
The answer I've most heard and makes most sense to me is that pole sleeves distribute stress more evenly and over a broader area. This was what Moss tent maintained, for example. Suppose only scientific tests could tell us whether well reinforced clips can do as well.
But the sleeves must be sewn well into the lap or flat fell seam, and because they will get constantly poked with pole tips during threading, must be a stronger (read heavier) material. You can note this on a TarpTent Scarp or Moment. And that may add as much weight as clips with reinforcements. That is why I'm trying to figure a way to get internal poles easily installed and stabilized. And as you point out, they don't create little snow fences (or rain collectors) either.
Sam Farrington, Chocorua NH

Derek Goffin
(Derekoak)

Locale: North of England
Cuben Tent on 12/22/2009 04:27:17 MST Print View

I have enough of the .75 breen cuben to make my tent design. I intend to make a cuben mid for 2 with a single trekking pole. That is all we carry. It is set up with string on my lawn at the moment, covered in snow. It is a bit like an SMD lunar solo but wider, (space for 2 behind the angled pole), with a relatively pulled out entrance vestibule to give more entrance room. It is basically an asymmetric 4 sided pyramid so the flattest triangular roof panels of the lunar solo are replaced by higher sloping ridges/edges that end in small triangular openable walls at foot and head. It is likely that the ends of the sloping ridges will be supported by 5mm CF tubes about 60 cm long a bit like our Terra Nova Laser. To get more width of head room each side of the pole I plan on guying out both central edges.(To look at the lunar solo one would be just above the entrance door one a bit lower on the back edge)It is likely to be worth pushing both guy out points apart internally with an horizontal CF rod between the guying points. This rod will be at about 37- 39" high. There should then be 6 perimeter guy points at the corners,4 long guys pulling out the 4 edges at the ends of the described CF poles and maybe 4 mid panel elasticated pull outs.
I bought some aqua seal and Steve Evans has sent me some hysol 09fl. You cannot buy it in Britain. I plan the perimeter tie outs to be dyneema cord loops with the core ends unbraided and fanned out into glue and another say 4" semicircle of cuben sandwiched over and pressed until set. No sewing if the hysol works well. The other tie outs do not pull wholly in the plane of the cuben so will be more tricky.

If this works as a non midge proof tarp tent. I would probably make an inner of: silnylon floor, lighter cuben and large panels of midge net, for use in the winter and the midgy times.

I think the design covers most of Samuel's feature list except perhaps: too many pegs and non free standing and a maybe a bit of contortion to get in. Another unmentioned feature, the slope of all faces of this mid is about 45 degree so condensation in the inside of the tarp should nearly all run down rather than drip off. With low through, and high ventilation condensation should be minimized anyway

I have taken on board the suggestion of trying this with space blanket first. So next step get more space blankets.
I struggle with photos and graphics except on paper so the best I can suggest to visualize is look at the lunar solo and imagine the differences. If anyone can see where I am going wrong it would save me from the expensive mistake when I commit to the cuben.

Edited by Derekoak on 12/22/2009 08:51:02 MST.

George Geist
(geist) - M

Locale: Smoky Mountains
Re: Cuben Tent on 12/22/2009 10:10:05 MST Print View

> I have enough of the .75 breen cuben to make my tent design. I intend to make a cuben mid for 2

Hi Derek,
Thanks for the description of your tent design. How many yards of Cuben do you estimate it will take to make your mid for 2?

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Re: cuben tents on 12/22/2009 15:06:44 MST Print View

Hi Miguel and Sam

You can see this design in the supermarket selling for $40. Having the Messner name on it means ... zilch. The high price means zilch (think sunglasses, watches, fashion clothes, ...). It is still just a pop-up with a door which will let the rain in. And it will still be difficult to pitch in a storm. Ventilation?

> the issue of clips versus sleeves and wonder why clips are considered inferior?
Stress concentration. May not matter when everything is 12 oz canvas, but it does matter when using UL fabrics. You must distribute the load.
All my guy rope attachments use large triangles of fabric to spread the load along the seam/stitching. Small bits of tape can pull out easily, for several reasons.

> We use tremendous force on guylines, much greater than on roof panel sleeves,
Really? I don't think so. Can you imagine hanging a 20 L bucket of water (20 kgf) off a typical guy rope attachment point? Pity the poor tent! Forces, yes, but not 'tremendous' ones.
A reality check on all this is to arrange a simple test load using a tent stake, a guy rope, a pulley and a large bucket of water. See what force is needed to move a typical small stake in snow or soil. Very few (experienced campers) report losing tent stakes.

I would guess that the forces on the roof panel sleeves (ie parallel to the poles) would be about the same as on the guy ropes, although I haven't actually measured the former. But I know what thickness bungee cord I use. A few kgf perhaps.

> roof panel sleeves, which normally pull at only one point, and yet also require
> the load to be as spread out as much as possible. Why should clips be any
> different that way?
With guy rope attachments the load is (normally) at 'right angles' to the seam (well, off sideways, at least). You can actually pull the stitching out, hole by hole. If the load is spread across a narrow bit of tape the force per stitch can be very high.
Tension on a roof sleeve (assumed parallel to the pole/sleeve) is usually applied along a length of seam (I hope) rather than just a short tape-width). Once again the load is more distributed.

> Don't clips also relieve some of the stress by not acting as wind-catches?
Yes - in principle, but in practice the wind-loading on a sleeve is very small. The wind loading on the body of the tent would be WAY bigger.

> But the sleeves must be ... must be a stronger (read heavier) material.
Why so?
I have never used a heavier fabric for my tent sleeves, and they have taken a lot of use (and abuse). No signs of damage.
Can't say the seams have shown ANY sign of damage from being 'constantly poked with pole tips during threading' either. But then, I take some care when pitching the tent.
That said, it is worth noting that a sleeve has two layers of fabric going from the pole to the main fabric, and so is twice as strong as a single layer anyhow.

> little snow fences (or rain collectors)
??? Can't say I have ever seen this happening on a tunnel tent. I guess it might happen on a dome though?

Tent design - FUN stuff! :-)
(Then you get to sleep in it, while wondering ...)

Cheers

Derek Goffin
(Derekoak)

Locale: North of England
Re: Re: Cuben Tent on 12/23/2009 03:10:36 MST Print View

Hi Al,
6 running metres for the outer only is my estimate. I have 9 metres but also have other projects planned

George Geist
(geist) - M

Locale: Smoky Mountains
Re: cuben tents on 12/23/2009 08:21:14 MST Print View

> That is why I'm trying to figure a way to get internal poles
> easily installed and stabilized. And as you point out,
> they don't create little snow fences (or rain collectors)

Hi Sam,

Why can't the poles be slid through sleeves sewn on the bottom side of the fabric? Am I missing something obvious?
The sleeve would stabilize the pole and there would be no snow fences/rain collectors on the outside of the tent.

Feeding the pole in from the edge, I can't envision that it is any harder with the sleeve on the inside, as long as the sleeve was continuous. (If the internal sleeve had gaps in it then yes I can see that would not work because as I threaded the pole it would get outside the sleeve, inside the tent where I could not reach it.

Diplomatic Mike
(MikefaeDundee)

Locale: Under a bush in Scotland
Pole sleeves on 12/23/2009 08:43:01 MST Print View

That sounds pretty good, Al.
Internal sleeves that are accesible from the outside at one end only are used on my Stepnensons 2R. I've wondered why other tent manufacturers don't all do it that way. I suppose there must be a reason?

Lawson Kline
(Mountainfitter) - M

Locale: LawsonEquipment.com
Sleeves on 12/23/2009 13:49:49 MST Print View

Manufactures don't use internal sleeves because they could care less about making quality products plus it would cost too much money. I personally think nothing is better than internal sleeves because you can construct a stronger seam above and the sleeve can act as bridge to distribute the load across the seam.

Franco Darioli
(Franco) - M

Locale: Melbourne
Cuben Tent Question? on 12/23/2009 14:51:33 MST Print View

"Manufactures don't use internal sleeves because they could care less about making quality products"
plus it would cost too much money

Yep, that is right. ALL manufacturers (they work together on how to deceive us silly consumers...) make shoddy products.
But, as you hinted at in the second part of that statement, if they did make quality products we would not buy them anyway because they would be too expensive.

Have fun with the internal sleeves...

Franco

Ross Bleakney
(rossbleakney) - MLife

Locale: Cascades
Re: cuben tent on 12/23/2009 15:08:48 MST Print View

"Ross,

Sorry I didn't address your comment earlier. Good idea on the 2 person design using both parties trekking poles. If you go alone you can bring poles for the rear.

I was thinking of going with a front width around 54" and a back width around 40" and a front height of 42" and a back height around 30". What do you think?"

No problem, there is a lot going on with this thread. In general, yes, that sounds like a good idea. I think I would make the back width about 42 inches. Two 20 inch pads makes 40 inches, plus a little room to maneuver them.

It sounds like you've just re-engineered the Squall (http://www.tarptent.com/squall2_2.html). :) That is a compliment, as I think the Squall (which is basically a two person version of the Contrail, is an outstanding design that is extremely popular for a reason. Obviously, lots of folks have contributed to the idea, but Henry, in my opinion, has crafted the best version of it. Unfortunately (for me, not you) he hasn't shown much interest in developing a Cuben version. You might be able to get a pattern from him, and then make your own tweaks as you see fit. I think there are a fair number of patterns bouncing around, if that helps you in any way (as well as a lengthy discussion here http://www.tarptent.com/projects/tarpdesign.html). Oh, and I don't mean to suggest you are stealing his design -- I think this is just a logical design that comes out of a desire to use trekking poles and have ample headroom.

Stuart Allie
(stuart.allie)

Locale: Australia
Re: Sleeves on 12/23/2009 15:57:33 MST Print View

One practical reason for external sleeves is that, in the even of a broken pole puncturing the fabric, the hole is only in the sleeve, not the fly, so the tent remains waterproof.

Samuel C. Farrington
(scfhome) - M

Locale: Chocorua NH, USA
Cuben tents on 12/23/2009 19:13:42 MST Print View

Roger,
Agree that if you are careful, stakes can be critical tent supporting points and pole sleeves can be of the lightest fabric. Being alone in a gale, whiteout and/or hail storm, or just simply being exhausted from slogging, hypothermia or an unfortunate injury, do not promote being careful. Idiot proof may be a pejorative, but I'm not embarrased to admit that it works best for me and friends I make gear for. I still believe there was a good reason why Henry used heavier fabric for the sleeves on the Moment and Scarp. Hope to put a carbon pole over the Moment and find out this summer how well it works to make the tent freestanding. (Idea: Instead of twisting the one ribbon sewn perpendicularly across the pole sleeve, remove that ribbon, and sew on two ribbons crossing diagonally over the sleeve with just enough slack for the pole to slide through under the cross).

About snow fences and rain collectors. First, I should have been clear that my posts were about single wall tents, since this is BPL, and my feeling is that single wall is the only way to get the best shelter in the lightest zone, Terra Nova and others notwithstanding. Having said that, I think that anything adorning the outer tent roof or canopy is going to create some retention of snow and water, even if all the poles follow the fall line on the canopy, but even moreso if they don't. Even if a pole sleeve just channels water vertically, it is still concentrating water on a more limited area than would be the case if there were no external sleeve. That's why carpenters put flashing and/or that sticky stuff, bituthane or whatever they call it, at the points on a roof where water collects and drains. OK, and I admit that a tent just looks more aesthetically pleasing to me with a clean, unadorned outer canopy. Henry's approach to sleeves on the Scarp and Moment is about the best I've seen, because the sleeve is only at the line going directly over the apex, or highest point, to the ground, and there is only one of them. The yellow color to contrast with the rosy gray canopy is a nice touch also.
But once you start crossing poles, as must be done for a dome or freestanding design (greatly enjoyed the recent humorous BPL thread on freestanding single pole designs), a number of complications ensue, including more snow and water collection, and more difficulty with threading the poles through the sleeves; ergo, the popularity of clips on domes like the Messner. Roger, please don't get the wrong impression; I love your design, and I also love the Moment design even though I know it would not protect me anywhere near as well as your design; but that doesn't hinder me from trying to build a better mousetrap.

Al and Mike,
There is an inner pole sleeve on the fly covering my Wilderness Equipment bug hut, and it works fine. However, inner pole sleeves generally do not stabilize the pole unless it is running inside a corner seam that limits movement, and even then, some manufacturers feel that instead of an inner sleeve, Velcro or other types of ties must still be added at points along the inside of the corner seam for stability. Also, inner sleeves would be even more difficult to thread without poking through the fabric, as there is less visibility than with sleeves on the outside. And if the poles cross inside? Yikes! It always helps to be able to see what you are doing. So cannot agree that there is any fault with the manufacturers on this score. Unlike us, they have no choice except to be idiot proof. Just about every aspect of Warmlite's design has been copied except the internal sleeve. Must be a reason. Patent or prudent? William Kemsley's Backpacking Equipment Buyer's Guide (1977) stated of the Warmlite: "You plug the shock-corded sections into one another while slipping them into the pole sleeves. It is an awkward operation the first time you try it, but once mastered, goes quickly and easily." Never found out, because did not want a tent that let the rain in when the door opens.
Cheers,
Sam Farrington, Chocorua NH