I have been working for some time on the idea of a small Mid type shelter for above treeline solo use. I wanted to base my design using exterior V'd hiking poles, in sleeves, to allow the most useable floor space while providing strong shelter support. The shelters low profile allows for a very strong, and wind resistant, pitch. I've just completed a tyvek prototype that is shown in the attached pictures. (do to a major snow storm I'm posting pictures taken with the shelter set up indoors)

here is the AlpineMid entry side view:


Non vented end:


Vented end:


The non entry side:


The AlpineMid with door open:












The exterior V'd pole sleeve:


The measurements used were 96" long x 42" wide x 42" tall. Weight as shown with bonded seams was 18 oz, this can come down a lot with sewing and with smaller seam allowances.

I hope to work with someone to fabricate a first run using silnylon with reinforced tieouts and pole sleeves. I plan to continue working with the tyvek on future prototypes (taller and longer) because I enjoy working with the material and I have yet to learn to sew.

I will be interested to hear thoughts and comments from BPL members.

Thanks to those who allowed me share the idea while I developed this first prototype.

Thom

Edited by thomdarrah on 12/27/2008 07:44:40 MST.

Looks great Thom. Is the vent near the top held open with something, or just by the crease in the tyvek? How will the door stay closed/open?
My personal opinion is that you should make the plunge and start sewing your prototypes now, better to start learning on prototypes than trying to figure it out last.

I just re-read your post, and saw that you are going to work with someone in the sewing of your silnylon model... maybe you arent ever going to try doing the sewing yourself?

Great project so far, thanks for sharing.

Peter,
With this being a prototype there are design elements that are not complete. The vent would have a stiffened brim and the door would use a zippered closure with double slidders on a production version.

As a prototype there are fabrication methods used for simplicity. Notice the black ducttape reinforcement at the tieout locations.

The prototype is built to verify that the working drawings are constructable and to identify design flaws. Notice that the end material does not underlap the peak vent enough, this will be corrected.

I'm posting the project to help identify that the concept has merit.

Thom,
Having just received a DuoMid from Ron @ MLD, I am very interested and impressed with your prototype. I too have yet to learn how to sew so I feel your pain :)
At 42" wide, that is plenty of space for 1, and since it is floorless, digging down is an option. There are a few guys on here sewing tarps, so maybe one of them could give this one a try in silnylon maybe?
I like the V-config as it gives much more room inside. I also like the pole sleeves, but was just thinking...could you get away with just 2-3 loops along the side instead of an entire pole sleeve? It would save material (and weight), sewing, and seam sealing...Just thinking out loud, maybe you need it for stability.
Great work, keep us posted.

Steve,
Thanks for the feed back. I wanted the full length pole sleeves to add strength for above tree line wind deflection of the long side panels. Maybe a half length sleeve would provide the same result.

I would like to produce a run of five to ten using silnylon and if reviews are positive I would then want like to do a run using spinnaker and cuben, maybe five of each.

The photos show the tyvek not as tight as I would like in some areas. This is largely the result of the shelter having simple tieouts (a hole puch used through duct tape and the doubled tyvek seam) that I could not really pull as tight as I would like. Also the tyvek, being brand new, was very stiff.

What pole length are you using for those pics above?

I used Leki adjustable poles set at 130. My fixed length Stix were to short.

"full length pole sleeves to add strength"

I suspected that was the case. We're probably talking grams at this point.

I would think that a pattern like your tent wouldn't be too tough to sew (just my perception, I really don't know if it is or not). Would it be a long shot to go to your local fabric supplier and see if someone wants to make them? Or even a local tailor? That is of course if you don't find someone on here.

My first preference would be to work with someone who has experience with both the materials and the application/use. Nothing about my design/concept is reinventing the wheel, tieouts, linelocs, peak vents and zippered access have all been applied with success on existing shelters. What is unique is the small solo size (for a Mid type floorless shelter), the V'd exterior poles and the pole sleeves.

Well, the inverted V has been done before:
1. Shannon's Golite hut 1 with internal inverted V poles
2. Dondo's ID silshelter with outside inverted V poles
3. Tarptent sublites with outside inverted V poles
4. MLD duomid (special duo mode) with inside inverted V poles

Still, your design is interesting though with the silnylon stretch it will be hard to keep things taut having exterior poles in a sleeve (with rain you have to go outside to adjust for a saggy shelter?).

I'd like to see your shelter shape, but with the poles internal so you can adjust easily for sagging. You could stake down this shaped tarp, jump inside with your poles and put it up in seconds. Internal poles would also allow for fixed pole lengths, preferably from 120 cm up to 135 cm(what most would be using). The floor ends could either be pointed (sildiamond floor shaped ; )) with floor dimensions of abouts 9' x 5' or have the squared bottom like yours at 8' x 4'. If somebody don't make this shelter, I am..lol.

Edited by jshann on 12/15/2008 14:07:17 MST.

Options are many.
I like the exterior pole design for various reasons, either option has strengths and drawbacks. I would be willing to make design modifications to the shelter based upon input from who I work with for fabrication.

I would opt to use silnylon for my first production run (when I can find someone to work with). Silnylon provides a good cost/performance/weight ratio. With positive feed back I would look at lighter and more expensive fabrics.

Edited by thomdarrah on 12/15/2008 16:29:16 MST.

Thom
I too would suggest you re-think the full sleeve concept. As it is I cannot see how you could easily/quickly adjust the height of your poles to put the shelter back in tension once the silnylon has "relaxed" . For the same reason I would avoid fix length poles also.
Franco
Deleted some killjoy comments..

Edited by Franco on 12/15/2008 15:49:31 MST.

Very clean.

Pole Sleeves: these make it rather rugged. Use above the tree line? Very possible. Add plenty of guy line tie-outs, and reinforce these on the **inside**. Allow a few stake loops at the middles of the bottom edges: they can be valuable in high wind.

Seam allowances: don't make too small with silnylon version, and allow for a doubling over before the final seam. Silnylon is tough, but give it some support.

Consider some guys on the corners rather low to the ground *as well* to help keep the bottom of the walls off your face and feet.

Mosquito net across door-way? You could just let it hang with a good cross-over and a couple of snaps rather than a full zip. It could be a blessing in warmer weather, and yet weigh very little.

Top ventilation: crucial!!! Cover the hole with no-see-um on the inside. Use whipper-snipper cord to stiffen the edge of the hood. Allow for lifting the bottom edge a bit for inwards ventilation - also essential.

Cheers

"I would like to produce a run of five to ten using silnylon and if reviews are positive I would then want like to do a run using spinnaker and cuben, maybe five of each."

Thom - I'd be willing and interested in testing and reviewing a prototype of the shelter. In central and western Kansas we get some serious winds that would nicely simulate Alpine wind speeds. In my opinion this would be a nice "lower risk" testing ground...

Franco,
I'm well aware of the design limitations and will be interested to see actual performance of the shelter in varied conditions. A production version with linelocs located at all corners and the peak would allow for simple retensioning.

I will be building two additional tyvek prototypes to provide to a couple BPL testers in exchange for user comments and pictures. I hope to have these ready to ship by mid January.

With the hiking poles coming togeather above/higher then the peak the shelter can be retensioned simply via the tieout. Tester feedback and my own personal use may result in design modifications or changes.

Thanks for the input.

Brian, If you would be willing to test a tyvek prototype let me know. (I will not have silnylon versions untill I can find someone to produce the shelters for me.)

Edited by thomdarrah on 12/15/2008 16:15:04 MST.

"If you would be willing to test a tyvek prototype let me know."

Thom - Testing the tyvek version would be just fine. Like I mentioned earlier I have driving distance access to some windy areas of the state. I plan to be out at least twice this winter here in Kansas. I will also be able to use the shelter on an early March, high elevation (11K+), cross country ski trip. On the later trip, there will be plenty of "4 season tents" in use by other team members that I could crawl into if needed. I'll PM you my e-mail address.

Brian,
Your on, we will talk over the details when I'm ready to ship. I will be shooting for 1/15/09 give or take.

Hi Thom

> (I will not have silnylon versions untill I can find someone to produce the shelters for me.

Sewing silnylon on straight seams is not that hard. Lots of pins and a fine thread and a low tension.

Cheers

Thom,

Have you thought about using type 14 rather than housewrap? Isnt 14 more water resistant than housewrap? ...and lighter? and by the way, it is a beautiful piece of work!!

Edited by johnk on 12/15/2008 21:58:10 MST.

John,
If in the future I were to produce a tyvek version I would select type 14. The tyvek used (construction grade) worked well for fabricating the prototype. Its tough, bonds well and I have a good quantity on hand to work with. My goal is to produce a silnylon version first and proceed from there.