4p, 3-Pole, Single-Wall A-frame Tent?

[Christian K]

Hi all,

Looking for some advice on a 4p, 3-Pole, Single-Wall A-frame Tent and whether there are any red flags with this design.

I was previously playing around with ‘mid designs for a 4p tent to use for my family (2 adults, 2 kids) or my 3-man adventures with buddies. I had settled on something similar to a MLD Mondomid w/ perimeter net and a detachable bathtub floor, and a peak height of about 6’8″. However, I’m worried about  a few things with having a tent that large, and mainly wondering if “living” space will be a major issue.

I recently went back to the idea of making an A-frame style single wall shelter (like GG’s the Two or the Zpacks Duplex), but making it wider to fit 4 people and using 3 trekking poles (or 2 poles and a CF pole). I think in most circumstances, 2 sets of poles (i.e. 4 poles) would be available. The center pole is to increase the ridgeline from what otherwise would be natural sagging. I know I’d have to taper the panel edges correctly.

Here’s some of my thoughts:

• Bathtub floor: 8′ x 7’8″x8″
• 2 outer poles at 48″ tall, center pole at 54″
• Zpacks style overlapping doors (no zipper).
• Sewn in mesh doors.
• Mesh at head and foot to increase ventilation.
• Materials: 0.93 oz membrane silpoly, 1.1 oz or 1.9 oz (30D or 70D) silnylon bathtub, and 0.67 oz noseeum mesh. Probably would choose the 1.1 oz nylon and a polycro sheet underneath.
• Nominal weight of the fabrics using actual OSY values is about 32 oz. Add another 25% for cordage, tie outs, seam seal, etc. and that brings my total to 40 oz (2.5 lb) w/o stakes and poles.
• I’d like to include a top vent too, but that might be a little tricky.

Here are some general pictures (cut away and fly/vestibule):

Alternatively, are there any issues using just two poles (and nixing the center pole) and raising them up to 54″ to account for the ridgeline curve? An 8 ft span seems pretty long to me, but I see that distance on tarps all the time. Any issues with condensation inside the tent funneling towards the center of the ridgeline and getting rained on?

[Jan Rezac]

If you’re not happy with a simple pyramid, I’d for a 2-pole design. Either just a rectangular 2-pole A-frame / mid hybrid, or experimenting with two poles on a diagonal of a square footprint (to get more sloped corners). Pitching such a 3-pole tent with all the poles aligned and sides taut would be more difficult. Also, you can make two strong and long poles out of two pairs of trekking poles, but in a three-pole design, two poles would be used alone, what limits their height to less than what’s useful for such a large shelter. Also, I’d consider silnylon over silpoly for strength when building any large shelter.

But all this of course depends on the conditions where the tent is used. I’ve made a large silnylon mid I use for winter camping, and there were occasions when it was needed to reinforce the center pole (two BC ski poles tied together) with another pair to prevent dangerous bending. Also, the strength and eleasticity of silnylon provides more safety margin than silpoly. It can be pitched very taut so it holds the shape well. If the fabric sags because of moisture, I just extend the center pole without even leaving the tent. But it does not happen very often.

[Edward John M]

My “thought experiment tent” has been a stretched pyramid using 2 poles to get something like the old MSR twin brothers but taller for standing room MSR used to do one but it was DFR’ed long ago although it is still available from AliExpress by 3F-UL

[Roger Caffin]

The major red flag I can see will be the fairly long fabric spans: they won’t like high winds. You may need to add a fair number of guy rope attachment points.

Cheers

[Author]

Posts