1 Person, 2 Pound, Dble Wall Tent

Does kitty go backpacking with you?

Project salvaged after 35 years. There's still hope for me after all!

My one person, double wall 4 season tent has lost some weight. It now comes in at about 1.5 lbs (instead of most recent 2 lb weight) for fly, tent and poles. I'm now pretty close to half the original mid 1970s weight of 2.9 lbs for this tent.

I replaced the 8 ounce aluminum pole set with a myog carbon fiber set that weighs about 3.5 ounces.

John at Bearpaw made a .74 ounce cuben fly to replace the 1.5 ounce(+ coating) nylon one. The cuben fly is a bit bigger than the original fly and weighs about 8 ounces with linelocs and guy lines…. instead of about 12 ounces for the nylon fly.

I eliminated the zipper on the fly by elongating the vestibules a bit. This allows me to raise either vestibule to about 30" for entry and/or ventilation.

Here are some photos:

Very cool Daryl. I'm glad you share your tinkering with us, always fun to see the creative process!

Wow Daryl,

that looks sweet! You're a busy man!

want to see the whole thing, nice fly

Daryl,

Info on a couple of points about the end covers would be most helpful.

First, are the long seams completely straight? If not, how did you calculate and mark the curvature?

Second, relating to your comment:

"I eliminated the zipper on the fly by elongating the vestibules a bit. This allows me to raise either vestibule to about 30" for entry and/or ventilation."

No doubt you saved weight by eliminating the long zip. But will you be as happy with the 30" height for entry/exit? Please let us know.
Thanks.
Sam

Sam,

FYI take a look at Lance Marshall’s Catenary Curve Spreadsheet.

Follow the link and click on Catenary Curve Spreadsheet, the second item in the menu. If you are using Google Chrome it may show up in the bottom of your monitor as a “box” that needs to be clicked to get the spreadsheet to come up on your monitor.

Use lines 7, 8 & 9. Enter your seam length in the box on line 7. Choose and enter your degree of severity in the box on line 8. Your deflection in inches will appear in the box on line 9.

In columns A, B and C starting on line 14 you will see a set of measurements that you can use to plot out a pattern for a catenary curved seam. You can use that pattern to mark your material if you are interested in doing curved seams.

I hope this is what you were looking for.

Party On,

Newton

John,
Thank you very much for the link, and even more for the instructions about how to use it.
Am still wondering if Daryl used a curved seam, and if so, how much.
Sam F.

Samuel,

I used straight seams, no cat seams. I’ve made about a half dozen one and two person tents of this design over the last 40 years and have always used straight seams. There is some looseness in the fabric and cat seams would undoubtedly tighten things up a bit. On the other hand the tents seem to work fine as is so I haven’t been motivated to take the extra effort to curve the seams. If I had more experience sewing cat seams I probably would have gone ahead and given them a try. This is the first time I’ve had someone make something for me and given the expense of cuben fiber plus labor I was reluctant to add curved seams to my specs for John at Bearpaw.

Steven Evans has made a similar tent. I asked him the same question as you have asked me. He said he used straight seams but might try curved ones if he makes another one. Here’s a link to Steven’s tent (scroll down page to see it):
Suluk As you might have noticed, Steven is working on all kinds of interesting projects. The link is to his R&D page. He also has a page for products for sale.

I think the 30″ front opening will work fine for me. I experimented with the previous fly by moving the vestibule zipper up and down. Thirty inches was just right for crawling into the tent on hands and knees. The door to the inner tent is about the same height. For reference, Z-Packs Hexamid entryway height is listed as 28″. Eliminating the zipper and modifying the vestibules to allow roll-up entry also allows me to enter the tent from either side. I think vestibules like this would go well with the tent project you recently posted.

Ziff,

If you scroll up to the top of the posts you’ll see a link in my original post. It should take you to an album showing more photos, including the inner tent. I’m currently making a new inner tent to shave off a couple of ounces and to incorporate a couple of ideas I had.

Thanks for the interest.

Daryl

John,

Thanks for the catenary cut link. I love having all this info available with a few key strokes.

Daryl

say thats a very good design. lots in common with Samuels, his extra poles would make it bombproof. One question, why does everyone pitch them so high off the ground, ventilation i guess but looks like a wind trap to me. there seems to be an evolution to one desgn here, tent manufactures could learn a lot for free.

Samuel,

I set up my fly and used clothes pins to capture the looser fabric along the 6 long seams of the tent. I figured the loose fabric is what a good cat seam would eliminate. If you look carefully at the photo you'll see some of the clothes pins.

Looks like a cat seam with a maximum cut of 1" per piece of fabric(2" total), at the mid point of the seam, would be about right.

Daryl

Daryl,
Thanks for your detailed answer. That is just the info I was looking for.
Am still thinking seriously about lots of zip for a front end cover.
But yes, if it is a good quality #3 zip, like the ones available from Warmlite, it will add close to an ounce, or almost 2 oz for the two I would like. There are lighter zippers from YKK, maybe they are #2.5, that weigh about 1/8 oz per foot, have lighter sliders, and are fine for an inner net door; but the slightly heavier YKK used by Warmlite is probably better for exterior use on an end cover that will be exposed to the wind.

Ziff,
"why does everyone pitch them so high off the ground, ventilation i guess but looks like a wind trap to me…
For a long time I used double wall tents with flies that did not come all the way to the ground. First thought about this when a friend purchased the SMD one person 'mid (Lunar Solo?) and told me she was very uncomfortable in the heavy condensation during an all night rainstorm. Her trekking pole was short, so the sides came right to the ground. Then noticed that the GG One's ends extend well beyond the floor sidewalls, but in most pitches I've seen do not come to the ground – that tent has been well reviewed for control of condensation. Both are single walls. In a double wall with good venting, it may be a different story with a beathable DWR or net inner to shield one from the condensation.

But if using a single wall to save weight, IMO more ventilation is required to keep condensation to an acceptable level, acceptable to me, anyway. You point out that when walls or end covers do not come all the way to the ground, the tent will be more vulnerable to the wind. Can't argue with that, but there continue to be good reports of the GG One's performance in the wind.

I suppose it is a trade off. I would rather have the ventilation with some balooning in heavy wind, than a steambath with coverage to the ground all around.
It probably depends on where one will be using the tent, such as the wide open exposed terrain of Iceland or Scotland, as opposed to below timber or tree line in the Rockies or on the AT. My choice is probably also based on good experiences with tents with good ventilation all around, not to mention the reports of many shaped tarp users who are not having their tarps blown away when pitched raised above the ground. To each their own, I guess. All of these designs can be done with the canopy walls and endcovers coming all the way to the ground if that is what one wants. They do tend to weigh more that way.

Also, there is a big difference between sleeping under a tarp pitched several inches off the ground, and sleeping under a tent canopy also raised several inches, but with a bathtub floor that is recessed inside and attached to the canopy with some arrangemet for perimeter ventilation. That difference may be one of the best reasons for carrying the extra weight of a single wall tent.

The tent you want may be one that can be pitched high or low, depending on the setting of the trekking or tent pole length, and how the tent is staked. So you might want to look for that feature in designing or purchasing a tent.

Ziff,

Why pitched so high off the ground?

I can only comment relative to my motivation for doing so.

I'm trying to balance the following goals:

(1) To use the least amount of rainfly fabric that will keep rain, wind driven rain and snow off the inner tent.

(2) To get close enough to the ground to reduce wind movement underneath the fly. This is for warmth and stability.

(2) To have enough open space below the fly to ventilate (as you said) to reduce condensation and speed up drying of condensation that does appear.

(3) To allow enough vertical clearance at the ends of the tent so I can have cut off, boxed, truncated ends on the inner tent. Ends shaped like this give more internal space than ends that taper all the way to the ground.

My current best compromise is to elevate the fly about 6" off the ground.

Daryl

Daryl, thank you for your considered responses to my probing re tent height. My tentng is mainly in the canadian alpine, so its cold, wind, bugs. I notice though that that kind of high pitch is unique to this BPL community, its not seen in tent advertisements or in the field around here. i suspect its a function of warmer climes. I used to use a small tarp open on one side also a wind trap i had to be carefull where i put it and hope the wind wouldn't shift. In those days my tarp was light but the rest of my pack still weighed +30 lbs , now i have a full tent and my gear is 10lbs for an overnight.

Any pictures with your tent inside?

Kevin,

If you scroll up to the original post you will see a link "ONE PERSON". Clicking that should connect you to a dozen photos of the tent and fly.

The fly is blue in the photos because it is made of 1.5 ounce urethane coated nylon instead of the cuben fiber shown in my avatar.

Let me know if the link doesn't work for you. I could post a few of the photos directly if it would help.

Daryl

I recently completed a new lighter inner tent for this bivy tent using some of the .7 ounce Christmas Green nylon that was part of the group purchase a while back. This completes the trilogy. I have now replaced the tent, fly and poles for this project, thereby reducing the overall weight from 2 lbs to 19+ ounces. Photos and specs follow.

Specs

Cuben fiber fly weighs 8 ounces and was well contructed by Bear Paw to my specs. It is 4' high, 8 feet long and about 8 feet wide.

Nylon inner tent weighs 7 ounces and was poorly made by me. It is 45 inches tall, 6' long, 18'wide at the ends and 30" wide at the center.

Carbon fiber poles weigh 4.4 ounces and were assembled by me.

Other info

Ignore the blue tarp. It is there to keep the tent from getting muddy while photographing it.

This tent is aimed at keeping me bug free and dry and WARM. I can count on a 10-25 degree increase in air temps within minutes of getting inside.

The last photo shows my windbreaker covering the only mosquito netting in the tent. I use this technique to increase warmth if desired.

The inner tent is completely made of breathable, uncoated nylon. I rely on pack, sleeping pad and, possibly, a small ground cloth for a waterproof floor. Entire inner tent can be run through the washer.

Condensation has always been quite low in this tent. I think it is because I can keep it warm enough for the air to stay above the dew point. I think the warm moist air holds its moisture until it passes out of the inner tent and hits the colder fly.

Tent attaches to ridge pole with a single 5/8" quick release adjustable buckle. I can easily raise or lower the tent or disconnect it. Lowering the tent allows me to decrease the volume while sleeping for additional warmth, if desired.

A 6 foot zipper runs along the ridgeline. To enter/exit I disconnect the buckle at the peak of the tent, letting it drop to the ground, and then enter/exit via the 6 foot long open zippered entrance. It works well. The unconventional zipper location should also prevent hungry grizzly bears from finding their way into the inner tent.

Way cool Daryl!

I like the way you keep implementing your ideas. I live vicariously thru you and many others here! That weight is awesome.

Hey Daryl, want to bet?

KNOCK KNOCK

Bob,

Your photo proves my point. Those big fat paws couldn't possibly operate the small zipper pulls on the #3 zipper…….even if the bear was able to locate the unconventional zipper location.

Daryl

Amazing work. Superlight and super innovative. Thank you very much for sharing.

Hard to validate through pictures, however the shelter looks too short for you – especially the inner.

What are the exact measurements?