Zpacks announces a free standing tent @ $699
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Roger,
Brad is talking about Dyneema (DCF) material. Check the frightful photo on the reddit link. Have never noticed holes like that on any nylon, let alone micro ripstop (like Rockywoods 7D). On reading another thread today, saw another note that DCF lasts about 250 nights to 500 for woven fabric. This is part of what gives me the heeby jeebies about DCF.Noticed on another thread, a pic of your Red tent with just the side-guys staked. You were saying that just the side guys anchor the tent fine with no stakes on the bottom corners; except that one time snowstakes bit through your Spectra line, although that had been corrected by the stake manufacturer. Here, I see front guys, that are no doubt useful, but am wondering in what situations you would be inclined to add the front guy lines & stakes.
You did not comment yet on the most recent thread knocking silnylon for the sand sticking to it. Would be interested in your take. I’m also inclined to stick to nylon over polyester (woven, not Dyneema) until there are some good abrasion, puncture comparisons. Have you thought about this? Just to sweeten the pot, here are more photos of sagging silnylon that were posted recently:
There was a tunnel type what was worse, but could not get it to copy off the link.Mark,
I enjoy looking at Roger’s tents, because they are primo compared to those like the one in the OP. There is so much junk on the market, that it is a relief to see something that is well thought out. And some things I’d like to see, like Trekkertent’s Phreeranger or Saor, never seem to bet written up. I’m starting to think that BPL is a little promotion heavy and quality light, so enjoy coming up for air.Geoff,
So the discussion of vestibules to the ground goes on. Would mention though that the canopy over the sleeping area on my tents always comes flush to the ground, just not for the vestibules. Don’t use footprints extending into the vestibules either, because when cooking under them in the precip, want to have the stove on bare ground. Must have been inspired by all those flaming tent threads on BPL. In fact, just use a 1.3 oz 6.6 nylon floor only under the sleeping area with no ground protector. Turns out the overall weight is less, and the 6.6 is bomber. Less fiddle factor as well when trying to get the tent up in a hurry. The tent floor fabric is the one area where am willing to make concessions to weight. But do design the seam lines it so it can be easily replaced.That was DCF? Good Lord. My mistake.
I do note that while DCF is quite strong on the weave, it is far less strong on the bias. I wonder whether that was the problem? It could certainly account for it.a pic of your Red tent with just the side-guys staked. You were saying that just the side guys anchor the tent fine with no stakes on the bottom corners
Ah – I REALLY, REALLY doubt I ever wrote that! A tunnel tent simply does not work without the stakes at the end corners. Could you have got the meaning of what I was writing reversed? (URL to the picture?)except that one time snowstakes bit through your Spectra line, although that had been corrected by the stake manufacturer.
Yes, that did happen – after the Spectra was fretting on the cut edges of the titanium snow stakes under a 100 kph wind for 12 hours. A bit extreme.
I made the Ti snow stakes myself, and did indeed correct the fault once we got home. Fully discussed in my MYOG Ti snow pegs article. This is what my snow pegs look like now:
although the pink brickies line (right) has been replaced with a loop of 200 lb Spectra fishing line (so 400 lb total strength – enough I think). I mainly use the Ti wire hooks (left) rather than the NiteEyes carabiners (middle). The post-trip modification consists, as one can see, of putting aluminium eyelets into the holes in the Ti so the string now ‘rubs’ on only soft aluminium, and never on hard Ti. The actual guy lines from the tent rub on the round Ti wire, which is not abrasive.
Doug,
The appeal for me is the inner framework, that if well designed, will make the tent much more stable in high winds. The same is true of Roger’s tunnels, which have a framework, but are arguably more stable than a ‘freestanding’ tent due to the tension generated by the front and rear stakes, plus front and rear guys if used. Makes no difference to me if the tent is technically “free standing.” Think the past arguments in BPL about the definition of “freeestanding” are kind of silly.Roger,
Found your post that generated my question. June 5, 2019 in the Hilleberg thread:
” ‘I didn’t actually put stakes in the four spots where the tent stakes touch the ground.'”
“I have never done so either, summer or winter, and in fact my tunnels do not even have any provision for doing so. The side guys, the ones on the poles, keep the pole ends firmly ‘attached’ to the ground, even in snow.”This caught my attention, because the same is true for my pop-up, to use your expression. With the four guylines, staked diagonally away from the tent, the four corners of the tent are held solidly against the ground without staking:
Plus the two one peg vestibules make a total of six pegs. Sorry the guylines are barely visible. Believe it or not, they used to be in this photo. But hope you get the idea.@Sam
Complex subject, however since you asked …First of all, remember that wind speed at ground level (right at the grass level) is very low. That means that for a summer tent I do not need to run the windward vestibule right to the ground. That said, it is often the case that by the time the tent is pitched on a ‘wild’ site, the surrounding vegetation masks the hem line (typically 50 mm high) anyhow. I rarely pitch on prepared sites.
For my winter tent the situation can be a bit different. If the snow is soft I will have stomped a hardened platform down INTO the snow, so a hemline similar to my summer tent is still below the surface. If the surface is however rock hard (which happens), then I could be at some risk, as the wind speed across the surface of snow can be much higher (see for example pictures of sastrugi). But I have a ‘snow valence’ or ‘sod cloth’ around the sides and windward end of my winter tent anyhow. That gets snow piled on it.
Now, lets look at wind hitting the end of a tunnel tent. Some air will go around the tent, but some air will be deflected up and over the tent. This air will exert a downwards pressure on the tent, keeping it in place, at least at the windward end. Two big caveats about this must be remembered however.
First, if the windward end of the tent is not anchored HARD to the ground, it can shift back under the force of the wind, relax the fabric, flap, and let the wind destroy the tent. The windward end of the tent MUST stay taut and aerodynamic. You don’t have soft squooshey front ends to jet planes after all.
Second, if you let the wind blow INTO the tent, the tent may balloon out and start to lift up and fly away. That is what happened to our horse shed in the big storm: the wind entered the open side, it was lifted up and blown away (literally).
As for the wind blowing under the groundsheet and causing damage: that is blocked by the sod cloth across the ground and by the weight of the mats, gear and occupants. I would estimate that the sod cloth or surrounding grasses looks after >90% of that problem.
The matter of the span between poles is perhaps more relevant to side-on winds. I do not like large stretches of unsupported fabric because they can flap badly. However, I suspect that the strength of the 4 tightly braced CF poles might be an equal or greater factor here, along with the high longitudinal tension in the fabric.
I should add that the structure of the CF poles and their guying is more significant than it might seem. Double side guys provide a lot of support on the windward side of course, but the lee side pole helps keep the windward pole up in position very significantly. Of course, the lee side pole could bend outwards and let the windward side collapse inwards – except that it can’t when the internal storm guys are used. This image shows how that works.
The solid black lines are the pole seams and the orange lines are the double tent guy ropes, anchored ‘off-stage’. The blue lines are the inner tent, hanging off the red velcro connections. The solid purple line is the Internal Storm Guy, while the brown dashed line is an alternative which is not favoured.
Now let us imagine a strong wind coming in from the left, pushing the left-hand pole to the right. But the pole cannot move as the double guy ropes are holding it in place. This is good.
OK, now imagine the wind coming downwards – perhaps with a load of snow adding it’s push downwards. The (outer) side guys can not resist this downwards loading, so the poles will both buckle outwards – except that they can’t. The Internal Storm Guy prevents any outward movement of those corners, and while they are fixed in space the rest of the poles are not going to move either.
I favour the purple version rather than the lower dashed brown version because it connects more directly with the upper outer guy ropes, to make a fully engineered structure. That said, I think the CF poles are stiff enough for the lower version to work. A small point of convenience: I can duck my head under the upper version, while I cannot do that with the lower version. In addition, if the weather during dinner is not all that bad, I can leave attaching the Internal Storm Guys until we are lying down and going to sleep. Then I sleep well.
One should note that these general principals can be applied to some extent to other designs, even the humble 2-pole pop-up. They are NOT specific to tunnel tents. They can work very well with dome tents. Sure, the internal storm guy can obstruct your head space – but losing your tent in the middle of the night is a bit more inconvenient.
Cheers
>> Since the rear vestibule is just for gear storage,
Actually, while that is true for my old summer tent, it is no longer true for my red winter tent.
I decided that moving wet or snow-covered packs from the front or lee end of the tent to the back or windward end over all our gear and sleeping gear was a silly idea. So the windward end is now very ‘thin’. There is enough gap there that the fly will not touch the inner tent, but that is all.
> ways to design out openings for the wind at the rear of the tent.
Yes, very important You don’t want the wind ballooning the tent!
This is the rear or windward end. You can open it up to the ground in this version, but in future versions the zips will come only half-way down. You could use it as an emergency exit, but not for gear storage.
Note that you can zip this end door right up to the top, and even seal the top edge with velcro if you want. I had to do this in When Things Go Wrong as the wind was clocking ~100 kph all night. That worked just fine. The inner tent has the same arrangement: zips and Velcro.
However, the front or lee end does NOT have the velcro across the top. Nor do the zips come absolutely to the top. One MUST have some ventilation, both for the stove and for the humans!
However, please note that the above photo was taken during construction. I had not yet fitted the sod cloth around the edges or the mid anchor, and the end guys have since been significantly enhanced, as below. The mid-anchor is the little ground-level guy in the middle of the end door, with a NiteIze link. It stops the end door from bellying inwards.
These sorts of design features are not restricted to tunnel tent. You could take these ideas and use them on many other tent designs – although I think you would probably need the poles sleeved into the fly to get significant value from them.
Cheers
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