Pole Sleeves, Seams, and Ends for Dome Tent

[J-L]

I'm attempting to make a dome tent. I was able to make a prototype recently (using scrap fabric, kind of quickly cut and sewn together) and it turned out pretty decent. It is 93 inches long, 62 inches wide, and 43 inches tall. I chose these dimensions so I could use the poles from my Big Sky Chinook tent. Here is the prototype:

I used Christian's formulas/spreadsheet at the end of this post to get the fabric dimensions:

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=15103

At first, I was a little confused how to use the spreadsheet and I made a hugely wrong curve. But then I figured it out and sketched the curves onto some cardboard, so now all I have to do is trace out the ridgelines.

I plan on using SilPoly for the final version, due to the material's low stretch. It passed my "kneel, stand, and stomp on a wet-towel test" with flying colors, so I don't really have any concerns about its waterproofness.

With my prototype, I validated that the basic dimensions are good and that the curves are good too. I also experimented with the pole sleeve diameter and what type of seam to use. But I would still like some input:

1. I tried a pole sleeve that was 1.5 inches tall (3-inch diameter) and a pole sleeve that was 1 inch tall (2-inch diameter). 1.5 inches seemed too big, and 1 inch seemed too small, so I think 1.25 inches will be just right. What have other people used for pole sleeve sizes?

2. Here is the method in which I plan to sew the pole sleeves and fabric together. It is essentially a rolled seam. The outermost and final row of stitching (that will be exposed to the most stress) goes through 12 layers of fabric. It appears similar to Roger's seam found here:

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=62580&startat=20

Black is the pole sleeve, blue is the tent fabric, red is a line of stitching:

1st stitch:

2nd stitch:

3rd stitch:

It's not very difficult to sew (a little time consuming to do accurately, however). Any issues?

3. What are people's opinions on how to secure the ends of the poles? Grommets in webbing? Little pole cups? I was thinking of putting the grommet/pole cup on some webbing, then having that webbing go through a ladderloc (which is sewn to the tent fly). This would allow me to tension the fabric down to the pole tip if needed. What size ladderloc could someone recommend? I am undecided if the stake-out guylines for these points should be sewn to the tent fabric and should be adjustable, or if they should be simple loops extending out from the webbing/grommet tip.

[Pierre Descoteaux]

Many folks around here have much more experience than me but here is my 2 cent:
I used a 1.5inch (maybe slightly less) sleeve for my cuben tunnel. But the poles used are only 0.292'' in diameter. What I would change is the deniers of the silnylon I used for the sleeves. I went for 30d from Thru-hiker but since I will use the tent in severe weather, I should have sourced some 70 or even 100d silnylon. (I know some like the 30d for this application)
Sleeve and seams: I'd go for Roger Caffin's way shown in this thread: http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=62580&startat=20
He knows his tents but bare in mind that he makes TUNNEL tents not domes… So this may only be food for though.
My sleeves are closed at the far end and I use a flexible cap attached to some bungee cord to automatically adjust the tension. It is simple and so far it works great. Like these but from Black Diamond…
http://www.mec.ca/product/4007-048/little-king-ice-screw-cap/?Ns=p_min_sale_price&h=10+50001+50019+50283&f=10+50001+50283

And most of all: Thank you for your post. It made me discover the spread sheets to make a tent similar to yours with more crossing poles and a vestibule. Unless I make a tunnel once more.
Cheers

[J-L]

Wow, Pierre, those are small diameter poles. Mine are about 0.375" diameter. Why would you recommend higher denier fabric for the pole sleeves? It seems damage would be most likely to occur when inserting the poles. My pole sleeves will require a total of 0.86-1.1 square yards of fabric (depending on sleeve diameter), so using a higher denier fabric would not add much weight.

I'll have to read through your tunnel tent build again. Also interested to see your dome tent design. I haven't finalized the dimensions of the inner tent yet, but it will only take up about 3/4 of the tent width, leaving me 15-18 inches of vestibule space in the front. Kind of like this design, but double-walled and not assymetric:

http://www.flusslinie.de/winterzelt.htm

[Paul McLaughlin]

I would think seriously about putting the poles inside the fabric, as is done on the Bibler/BD tents. This gives you the most possible volume for the length of the poles.

Also, I would sew up the entire canopy except for the bottom seam/hem, and then test fit the poles so that you can fine tune for a tight fit and taut pitch.

I have a homemade dome with internal sleeves that I stopped using the sleeves on and just put the pole inside – worked great. That has tensioners on it – 3/4 ladderlocs, but 5/8 would definitely work and 1/2 would probably if you can find them. On mine, I sewed the webbing to the bottom of the fabric, with a grommet in the webbing for the pole end to go into. then the webbing goes up to the bottom end of the pole sleeve, about 6" above the bottom edge of the fly, where it goes through the buckle. Pull down, it tightens. It actually still works even with the poles not in the sleeves. On that rig I had installed little loops of 5/16" grosgrain every so often for clipping in an inner tent(which I never made). I now run the poles through those little loops – and I don't detach the poles from the tent, i just bunch up the fabric and slide the loops along the poles to the center of the poles, then I can fold up the poles with the fabric attached and shove the whole thing in a stuffsack. Makes taking down and setting up pretty quick and easy.

[Pierre Descoteaux]

Well, the poles I use for my tunnel are not pre-curved so I poked a hole in the sleeve during one of the multiple set-up required while working on the design. It was an easy fix. I added an external layer of 1.43osy cuben (white) to the far side of the sleeve. I should also say that it happened while using make shift aluminum poles that had a smaller than desired tip. I had to make due while waiting for the carbon fiber ones. It is easy enough to be more careful during pole insertion but I'd rather not take a chance while on a climb…
My new design is far from anything else than a few sketups… It will be a long while…
Cheers

[J-L]

Could you post any pictures of your tent, Paul? I don't recall finding any when I searched for MYOG dome tents

Do you feel like you lose any stability by having the poles inside?

By having the poles outside, it seems like there would be less possibility of the poles moving around (greater stability). I also think setting up a dome tent with internal poles and a separate inner would be difficult.

I think I am going to go with 30D silnylon for the pole sleeves. It's not meant to be a mountaineering tent, so it should be strong enough. Also, I think Tarptent uses 30D silnylon for their pole sleeves, and I do not hear of many issues with those.

[Paul McLaughlin]

I don't know if this will be of any use since mine is a 3-pole dome and this doesn't show much, but anyway:

Never posted anything on MYOG forum about it – this tent is way older than this forum is.

I don't think having the pole inside reduced the stability much even though the loops I have the poles through now are way bigger than they would be if I had intended to use them that way. If I were doing it again I'd use much smaller loops of grosgrain ribbon to keep tighter control, or I'd have internal sleeves – but I really like the way this setup works where I don't separate poles from fly, because it goes up and down really fast, and that wouldn't with sleeves.

But I do have one pole in a sleeve – the dormer pole that supports the dormers over door and vent – and that one is 30d silnylon – you can see it in the photo since it is red while the tent body is orange/gold. No issues with that and this thing has been through some nasty storms. I like the sil for sleeves – poles slide nice and the little bit of stretch is probably helpful in distributing stress.
As to the inner, once the outer is up I doubt it will matter where the poles are – in or out, sleeves or not. All that matters is a good system for clipping the inner to the outer. Mine has never had an inner. Now I can see , if you want to pitch the inner and outer together, how a sleeve would make that easier. But I think if I were doing that I'd still go with the sleeve internal. Really no harder to insert the pole – you're doing it from the edge either way – but you gain that little bit of extra room. Also a cleaner profile outside, should shed the wind slightly better.

[Roger Caffin]

My tunnel tents use CF poles, and they are 7.5 mm or 0.295" diameter. That seems to be pretty standnard for CF poles. Remember, CF can be stronger than aluminium, even 7075.

Have the poles inside the fly is OK, but the REAL requirement is not inside/outside, but 'tightly constrained'. If the fly can move around relative to the pole, it is not strong. But if the pole is tightly coupled to the fly, inside or outside, things are good.

Poles ends – different folks, different strokes. As long as the fly is moderately tight over the poles, all is good.

Cheers

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