Gear

I have been making adjustments to our Nallo 2 for a trip to the Andes and Patagonia where high winds are expected. I just made internal guys for the Nallo. I am impressed by how much stiffer the tent can be. The guys are thin webbing temporarily fitted with toggles across the hoops. They only weigh about 10 grams the pair.

The guys hardly get in the way. They go from the top guy point on each hoop across the tent to the other top guy point. The front guy does not even interfere with the inner it goes at about sitting face height just outside the inner door. It is easy to duck under it to get out. The back is a little more difficult. I have permanently fitted short webbing from the correct inner toggles horizontally across to the inner and added  webbing loops on the inside of the inner at those points. In a storm a 31" tape is toggled across the 2 loops. It is placed well above the ankles and feet of people in sleeping bags.

Advice from Hilleberg was tension the Nallo strongly front to back but do not tension the pole guys, just snug them up. If you over tension these pole guys you distort the hoops.

With these inner guys in place you can get a good bit more tension on the pole guys as the inner guy stops the distortion of the hoops. Without internal guys the up wind side of a tent hoop is supported by the upwind guy, but the hoop is still pushed over at the top by the wind, increasing the bend in the downwind side of the hoop. The suction on the downwind side has only the stiffness of the pole to resist it. The downwind guy is loose and useless. The pole is likely to break. With an internal guy and tighter pole guys the downwind side of the hoop is supported by the internal guy and the upwind side does not get pushed over so much because of the tighter guys.

Tonights the night for a test

 I may separate the top pole guy from the lower one as the lower one does not get an internal guy to resist the tension.

I recommend Nallo users who want more security in high winds to experiment. Tie a bit of string across the front hoop at top guy height and see how much stiffer the front hoop becomes.

I can take photos but I will not get round to it quickly. The simple one is the front hoop. Find the top pole guys. On the inside of the Nallo fly at these points there are  strong webbing loops (for  a toggle that supports the inner with elastic). To experiment just tie string across from one webbing loop to the other. now you should be able to get a little more tension on the outside guys.

If you dropped the back of the inner you could do the same with the rear pole. But with the inner connected it gets in the way.  My description above was how I got a straight line across the back pole through the inner.

Another thing it is would be nothing new.  Vango's Tension Band System being a pretty obvious example, and Stephenson supply them as optional extras on all their tents.

So why isn't everyone doing it?  Because there's a trade-off in convenience, as Derek illustrates with his description.

Pete.

Nifty. Let us know what its like in real use!

From reading things elsewhere from people who've had tent failures in really nasty conditions suggest that horizontal internal guys do an excellent job at keeping the tent together in descending winds on mountains; normal guying does nothing against that sort of damage. Hopefully you'll get nicer weather than that!

One of the hardcore MYOG guys on backpackinglight.com made his own tunnel tent with carbon poles and internal guy points...its stood up to some atrocious conditions without pole failures, which is interesting.

Peter Clinch wrote (see)

So why isn't everyone doing it?  Because there's a trade-off in convenience, as Derek illustrates with his description.

This doesn't explain why people who make hardcore tunnel tents don't at least have internal guy points available to use as necessary. It would all be much easier if it were already stitched into the inner.

Vango's TBS is part way there, but is clearly a convenience oriented design.

We went up Pendle hill last night to camp. We have no anerometer but predicted Met office maximum winds for 400m in the Dales and Peak district was 75mph. Pendle is over 600m. Mwis predicted higher

We camped on the flat top just upwind of the summit. We could stand and walk with difficulty except in gusts. Putting the tent up was difficult, the soil was poor and rock ridden. I have enough confidence in these internal guys that although we had double poles available we did not use more than one set. We got the tent up, with the wind unfortunately just off straight down the tent. The pegs were pulling out in the wind so we loaded the pegs with rocks. We have set the tent up with rock loops so we could also take the strain off the pegs by putting rocks in the loops. When everything was set and the front points tensioned the tent felt good but it was flogging and shaking continuously. The internal guys were tensioning and slackening with gusts, but mostly tensioned. I cooked in the porch. The front internal guy did not get in the way too much. You ducked under it to get in and outThe rear guy did not cause any problem until, feet to the door, I lay back to pull waterproof trousers on  then I had to get under the guy to lay down. In normal use it was not a problem.

The tent survived the night, with no damage that I have noticed. The wind reduced a little during the night. The problem seemed to be the pegging not the poles or the fabric.

Sleep was intermittent because of the noise.

I do not think there was any gusts from above, just because of where we were in maximum wind, as clean as it comes. My suspicion is downward gusts happen behind rocks or on lee slopes.

I think internal guys do a lot to keep the pole hoop in shape.

Serriadh is right a strut takes compressive force a guy or tie a tension force. I am only talking about tension forces.

A bicycle wheel is the perfect lightweight thing with a compressive rim and all the spokes in tension. A tent hoop is a bit like it. It seems daft to reinvent the wheel without spokes, but that is what tent manufacturers have done! And the only excuse customer convenience. If the winds are mild you dont want things in your way but to be able to add a tension structure so your tent can cope with a gale without worrying you is a big asset, worth the odd wriggle!

And the only excuse customer convenience.

Fair's fair, that's a pretty big excuse! (though as you say, an optional-use anchor would be good.  I'll have a look in the Kaitum next time it comes out; I imagine the possibilities for using the inside of the main guying loops as you've done in the Nallo  would be the same, but rather easier at the back (as the back is the same as the front).

Pete.