More cuben shelter advice needed.

[Rog Tallbloke]

Hoosier T has kickstarted me into doing something with the 5 yards of 0.51oz/yd cuben fibre I bought a while back.

This morning I cut up an equivalent sized piece of Tyvek and made this prototype.

With long side midpoint tie-outs attached, it’ll be just big enough for two. It’s pretty much MLD duomid dimensions.

I don’t want to screw up with my expensive cuben fibre, so I’m going to be asking many questions as I go along with this project – thanks for your help and patience.

#1 how important are cat cuts with non-stretching cuben fibre? If I should have them, how small a max deflection from straight can I get away with on a 77″ length?

#2 I’m in UK and having trouble finding the right tape to bond the sections. Can anyone buy and ship for me?

#3 What is the latest wisdom on corner tie-outs? Embed a small sheet of polycarbonate with drilled hole for dyneema cords?

Thanks for any replies, I hope to use the new shelter this year!

[Jerry Adams]

3M 9460 is supposed to slip less than other tapes, like 3M 9485, but that’s probably fine – Joe at zpacks

https://backpackinglight.com/forums/topic/90464/#770354

I’d have tape and sew it, just to make sure it doesn’t slip

There have been recent reports of lack of durability of Cuben, plus lightweight poly and nylons, so I think I might use that instead.  But since you already have the Cuben…

I’ve tried the A frame pole design and found it too constrained.  Get in there with your other person and move around a little, simulating getting into and out of the tent, fiddling with gear,…

[Rog Tallbloke]

Thanks Jerry. I don’t expect to be using it  much for duo trips, the missus likes the Hex3 roominess. Plenty of floor space for one ultralighter though, and I think having the entry on the end rather than side is the right choice either way. Wet entry can be made with sleeping gear well out of the way down the far end.

I agree it’s not a roomy design. 5 yards constrains design choices if you want full protection from the elements. Keeps the weight down anyway.

[Bob Moulder]

As you have mentioned — and I’ll throw another 2¢ at it to concur — the Duomid is really only comfortable for one person or, in my case, me and my 65 lb pooch. Two people in there is not feasible because of the head and shoulder room, although it could be alleviated somewhat by pitching it higher, but then of course there’s more exposure to weather.

[Rog Tallbloke]

It depends on style, location and attitude to some extent. The missus and I have been on two week lowland trips to sunny climes under a gatewood cape and several other times with a Golite hut 1 and had a fine time. My first jobs on waking are rolling over and getting a brew going, and then wiping night-time condensation off the tarp before we sit up. It’s a 2 minute chore that gives me a damp cloth to have a flannel wash with. Since I spoiled her with a hex 3 she’s gotten harder to please though. :)

I asked about the cat-cut seams because I’ve seen some myog tents and tarps with volume restricted quite severely by the curvature. Especially for sleeping head room near the ends of the tent.

 

[Mole J]

Rog.

On http://www.trek-lite.com ( UK ultralight forum)

There are a few UK based folk who have made cuben shelters,  and also know sources for tape etc.

<span style=”line-height: 1.8;”>E.g</span>

http://www.trek-lite.com/index.php?threads/myog-cuben-shelter.711/

[Rog Tallbloke]

Thanks Mole, I just checked that thread. Nice work. My effort will be a lot humbler. I just want to get the basics right before I go ahead and cut material, hence the cat-curve question. Maybe I’ll just forget those and put mid panel tie-outs in. :)

[Hoosier T]

I just finished mine up last night. Did my best to copy the Tramplite shelter (the one with the zipper), which if you’re not familiar with it, it’s pretty much the same as a Deschutes. I did not do cat curves. I’ll be pitching it tonight for the first time but I don’t suspect any issues without cat curves. I did add mid-panel tie outs to help if needed. For the tie outs, I basically copied all of the techniques from Leshy’s videos. The one for corner tie outs is below. They came out so nice and while tedious, were quite easy to make. I may have overbuilt the peak and tie outs and opted for a #5 WR zipper but I’m still happy with the 9oz result.

[Rog Tallbloke]

Mid panel tie out tension will pull a bit of curve into the edge seams anyway. Show us some pics soon!

[Jerry Adams]

I question the idea of mid panel tieouts

It puts the panel above under tension, but below the tieout it goes slack

Better to have more tieouts at the bottom along the perimeter.  Then the entire surface of the tent is smooth and even

I’m not sure about this, more of a theory.  This hasn’t resonated with other people.  Anyway…

[Bob Moulder]

Mid-panel tieouts are IME a good thing with the silnylon Duomid and I suspect they’d also be a good idea with Cuben pyramids as well.

If memory serves, Cuben mids from MLD, Locus Gear and HMG also have mid-panel tieouts. However, I don’t know if Cuben and silnylon present any different considerations when pitching. although it is well known that silnylon stretches and Cuben doesn’t. But it is stupid-easy with a silnylon pyramid to compensate for stretch by lengthening the pole or poles (for my inverted V pitch).

One of the nice things  about the inverted V pitch (in addition to no pole in the living space!) is that the side walls are prevented from blowing inward by the poles, so no tieouts are needed on the side panels unless you’re getting very heavy wind that stresses the poles too much.

With the silnylon Duomid there might be a little slack at the lower edge, but it isn’t much, and the extra few inches of head clearance when sitting up are worth giving up a tiny bit of space, if any, at ground level.

When it’s snowing, the tieouts are preferred, no question (last photo)!

[Hoosier T]

After one pitch with my new shelter I can say that I’m glad I didn’t give up the head room for cat curves. It pitches plenty taught without them.

[Rog Tallbloke]

Thanks Bob, that’s a really helpful post. I agree both with the necessity of the tie outs, and the advisability of an inverted V pole system for rigidity and panel support.

Hoosier T, thanks for the confirmation.

[Catherine Harley]

First, Thanks Mole for posting the link to my MYOG cuben shelter poject :-)   The inner is still ‘evolving’

Rog.

1. Catenary cut seams – not necessary. I didn’t use them, but a tiny bit of deflection say less than 1″ might make it easier to get panels taut. I didn’t want the faff.
2. Tape. I used the 3M tape sold by Extremtextil (expensive) on the main ‘load bearing’ seams. I used some cheaper ‘Viking’ tape on hems etc. Paul on trek-lite had some to sell – ask if he has any left. Not sure if there is much difference – but better sure than not.
3. Tie outs. I over engineered mine. Polycarbonate + drilled holes – not sure if the holes will hold etc ??   I’d  copy whatever the cottage cuben shelter guys do…….and make proto-types first. Re-inforcing the area around the tie out is important – see Gixers exploits with a Duplex in the Lake District – http://www.trek-lite.com/index.php?threads/2015-lakes-trip.1042
4.  Shape/Design. Having seen a Duomid – I think it’s too tall – catches the wind too much plus a waste of space/volume up top. You need enough to sit up in and no more. To get the greatest volume of space under any given area of fabric then the side walls need to be at an angle of about 45 deg. That’s the basis I worked with to get the most out of the cuben I had to make my shelter. I think I got it about right on that.
5. Mid panel tie outs. I didn’t want/need them. The big ‘flat’ panels on the Duomid seem a poor design feature – they need pulling out/supporting and catch the wind too. By adding an extra seam (effectively halving the panel) and pulling it out a bit to make a point/beak ……the seam does the job of the mid guy. The angle deflects wind and you get a bit extra space inside…..and the slight extra weight of fabric is offset by not needing the mid-guy + reinforcement. My shelter does deflect wind well in moderate conditions.  I’ve not had it out in strong winds, but if the pegs held I think it would be just fine.
6. End opening – do you really want the inside so exposed to what passes for the Great British summer weather every time you open it up ?  Zip only part way up will mitigate the exposure but then restrict entry/exit space.

Just my thoughts.

Good luck – it’s a steep learning curve. Any questions just ask.

 

[Rog Tallbloke]

Thanks for the helpful post Cathy.

I don’t think the duomid is tall in comparison to a Zpacks altaplex or Colin’s tramplite design. I’m 6’8″ and there is just enough room to sit up in the prototype.

I’m minded to compromise on mid-panel pullouts. I’ll put one at the far end to increase sleeping head/foot room. I agree that splitting long panels with a seam and pegging point is the way to go.

End opening I’ll think about some more. It does mean a shallower angle for the zip which is asking for trouble I agree. Looking more carefully at pics of the duomid, it does seem to have the apex offset to the door side by a few inches to keep it steep.

[Catherine Harley]

You could offset the poles towards one end – the zip end. Sleep/sit head to that end. Would help alleviate weather ingress, and if pitched away from the wind present less profile to the wind. I assume from your prototype pics you are pitching with an inverted “V” pole arrangement.

[Jerry Adams]

Okay, maybe tie-outs are a good thing, especially with that last picture and the snow.  I’ve experienced that in my mid, and you lose about a foot on each edge where the snow pulls the tent down, but hitting it from the inside fixes that.  Good pictures.

But, when it’s windy, I think it’s less effective.

[Rog Tallbloke]

Cathy, yes, inverted V with my GG LT4’s. Asymmetric is OK until you find yourself sleeping with your head downhill. That’s why I love my Hex 3, You can even reposition the door if the wind changes by hopping the tent round the pegs without going outside.  I don’t have anything like enough cuben cloth for that though.

Now I’ve made the prototype I have a much clearer idea of how much cloth I have to play with and what sort of tweaks to the basic pyramid shape I can make.

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