Making Another Tent Inner: Part 1 – Requirements and Design

After making an inner last year, it’s given me the confidence to do it again, this time with some refinements. I’ve now gone from a situation where the size, position and materials of a commercial inner no longer need to constrain my choice of tent – now I can just make my own. Provided I’m open to a rather homespun-looking result.

How choice of tent can be determined by the inner available

I’ve lost count of the tents I’ve turned over because the inner space and split between bed area and vestibule wasn’t quite right. Or where the only option is a fully mesh inner which didn’t work for me. Or where the theoretical size of the inner was belied by the practical experience. Or… a whole host of other reasons.

When I wanted a larger pyramid tent for the darker half of the year, the available inners really did drive the decision making. That larger pyramid needed to have enough space in the inner to sit up and move around comfortably, and just enough space to cook and change out of wet things in the vestibule. I was also looking for an inner made of solid fabric rather than mesh, as the added warmth and wind-blocking would be important at that time of year.

My search at that time considered 4 shelters:

  • MLD’s Duomid XL – an asymmetric shelter giving bags of inner space behind the single pole, and a shorter vestibule area. This was the perfect division of space, but the only inner available was mesh.
  • Luxe’s Minipeak XL – this had the amount of inner space needed behind the single support pole but at the cost of an enormous footprint and weight. I did consider whether I could use the inner with something like the Duomid XL, but sourcing it separately was a bit of an issue.
  • Something like Liteway’s PyraOmm Plus, which may be just big enough, but which also suffered from mesh-only inners. There were two choices – a solo inner that would go behind the pole (a bit small), or a duo inner which required an A-frame. The inners available on Aliexpress didn’t quite fit either.
  • Tipik-tentes Aston – an asymmetric octagonal shelter with a good amount of space behind the pole and a decent but not cavernous vestibule. The inner was made of solid fabric, so it was a no-brainer. There were a lot of things I liked about it, so that’s the one I got.

I loved the Aston for its perfect distribution of space, but less so for its noisiness in a bit of a blow – although the tent never failed, that large expanse of fabric at the back certainly made for a noisy and sleepless night. The red colour I went for originally, was also starting to restrict the scenarios I could use it in (and making my videos look like I was filming in a brothel). And the asymmetry made for a large expanse of fabric at the rear that could be caught by the wind. After putting up with it for a while, I decided I needed to sort the issue out once and for all.

On the flip side, I’ve loved the Liteway PyraOmm Duo I bought last year – a more traditional symmetric shape (although not so much in the case of the vent placement), but with a more pronounced catenary cut. It pitched easily, it coped with weather well. And having made an inner for it, that was designed to be used with an A-frame setup, I’d solved the division of space problem. Could the same solution, then be extended to a larger pyramid ?

Clearly I thought so, and the obvious choice was the larger model of PyraOmm – the Plus – that I’d ruled out before because of its mesh inner. Moreover, it was smaller than the Duomid XL, which also isn’t available to buy until at least April anyway.

I’ve finally been able to buy the shelter I want, unconstrained by the inners available – I’ll just make what I want. Out with the Aston, in with the PyraOmm Plus. And I came out slightly ahead in money terms too.

So the project from here on is to make an inner for this larger shelter. The size is a little bigger, but all of the principles are the same as the one I made before.

I’ll then assess the future of the Duo shelter before deciding whether to make an improved version of the inner for that.

Lessons from the previous make

In the Lessons Learned at the end of the post about the first inner, I noted a few areas for improvement:

  1. Increasing the amount of solid fabric on the back and sides – purely to retain more warmth.
  2. Possibly compensating with a wider strip of mesh on the front to maintain the overall amount of “ventilation area”
  3. Use something a bit easier to work with than the 1.1oz ripstop nylon I used for the solid peak
  4. I made a right hash of the zip. The idea was fine in itself, but the execution was terrible. Next time I’ll trust in the measuring and cutting to allow me to add it to the edge of panels from the start, rather than have to “cut through” after attaching it.
  5. Eliminate the pockets I built into the lower solid panels – they sag a lot and aren’t really very useful.

…and a few observations about the process itself:

  1. Making an inner is easier than making a tent as the pieces involved are smaller – with an outer fly you generally want to minimize seams and only put them where structurally necessary. With an inner it doesn’t matter, except for a fractional increase in weight added by each additional seam.
  2. A lot of measuring, due to the fact I was piecing together lots of smaller pieces.
  3. A prototype isn’t needed if you’re confident of the geometry (and can visualize how it fits together in sewing practice).
  4. My method for the bathtub corners worked well.
  5. I got lucky with sourcing the Hilleberg yellow fabric – I probably won’t be lucky like that again and will have to find something else.

Design Choices – SIZING and Position

For this make, the design is driven by a few key factors:

  1. The size of inner I want, specifically the width/depth.
  2. Where the inner would need to be positioned in the tent footprint (ie pitch area).
  3. The pitching options I will have

I thought deciding on size would be easy. Almost any other pyramid inner I’ve ever had would fit under the PyraOmm Plus, so all I needed to do was choose. But this was easier said than done.

Length was easy though – essentially it was the full width of the tent, less a pre-determined “clearance” zone to provide separation between outer and inner. I decided 20cm was about right for clearance on each side, leaving me 236cm to play with. So 236cm it was then.

For depth/width I initially went for 120cm which would give me overall about the same total space I had in the Aston inner. But I realised that may even be too much. So I started playing around, initially cutting up some of my cheap cotton prototyping fabric into a piece of about 240cm x 100cm. That seemed ok, but 100cm would give me acres of space for the vestibule – I might as well have some of that in the inner. So I compromised on 110cm.

That just left height. I could go anything up to just short of 160cm, but did I really need all of that? Indeed there was something to be said for going lower as that would enable the inner to be used under something else, for example the PyraOmm Duo. I mulled this for a while and decided to go for 140cm – and if I wanted to use it under the Duo I’d adapt it to do so, by adding in a secondary hanging point lower down.

Position was easy enough to decide. Liteway’s own inner is slap bang in the middle of the shelter, making full use of the fact there are doors on either side of the tent. I don’t really need this. Even on other shelter designed with dual doors, I tend to only use one anyway. Therefore, I would be positioning the back of the inner towards the back of the tent, allowing a clearance gap and see how far forward that made it finish. It would then be a matter of confirming the pitching options would work.

The above diagram shows the position of the inner and what that means for pole positions and lengths. I considered two main options: a slanted pole and an A-frame.

Pitching the tent and experimenting with pole lengths enabled me to validate what my real options are: basically they all work. The extremely slanted single pole does result in a bit more concave-ness (<<is that even a word ?) at the back so I probably won’t do that very often. Crucially, I was able to get an acceptable A-frame configuration, so it’s all systems go.

In the picture above, you see the Plus with the inner I made for the Duo. Notice the scope for a bit of extra length – the Duo inner was made to 220cm length. This picture also shows that pitching with a single slanted pole (including extension) is viable, although there will be a limit to how far you can push the angle of slant.

Most people would pitch a shelter of this size by joining two trekking poles together and having a single, possibly slanted, centre pole. But I’m fortunate in having 160cm long trekking poles, meaning that I could do a centre pitch with just a single pole. This also means when I add on the extra 30cm (less a bit for the overlap of the pole inside the connector tube) for the A-frame connectors, I have about 187cm to play with. That’s almost enough to A-frame the tent at maximum pole separation distance. But not quite. Pulling the poles in 10cm from the edge makes it comfortable.

Design Choices – Materials

The PyraOmm Plus will typically be used in the “darker” half of the year, when the nights are longer and the days are shorter, and when I’ll be spending more time in the tent. And on campsites where a bit more space to move about is always worth having. Exactly the scenarios I used the Aston in, but I’d also be more likely to use the Plus year-round.

It’s been mentioned a few times already, but the key fabric factor is the amount of solid fabric. I decided that I’d use about the same amount of mesh as before, and the extra size of this inner would all be achieved in solid fabric.

So, much deeper solid panels at the bottom all round.

Having got a crude idea of how much fabric this would take, I ordered what I needed from Extremtextil – the place I’d found the nearest thing to the Hilleberg inner fabric. I’ll be using 40D ripstop nylon. I could have gone for the 20D version but was concerned it might be a bit like the slippery orange stuff I used last time.

For the orange bits at the top, rather than use the remaining 1.1oz uncalendered ripstop nylon, I opted to order some more of the 40D ripstop nylon, but in orange.

For the mesh panels, I will use either my remaining stock of 0.9oz Noseeum, or eat into the 1.0oz Monolite ripstop nylon I’ve not used yet. I’ll decide that as I go – I originally bought enough Monolite for multiple inners, so I’m not constrained by the quantity of material on hand.

The bathtub will be made from one of two fabrics: either the same 1.6oz HyperD PU4000 I used before, or the 10,000mmH PU-coated ripstop nylon I included in my Extremtextil order. Basically, I’ll wait and see what the Extremtextil stuff is like when it arrives and go from there. If I opt for the HyperD, I have just enough (and no more) to do it.

This time, though, when I make the bathtub corners, I’m thinking of inserting some form of stiffening to maintain shape. This will probably be a piece of webbing embedded in the corners.

The webbing I’ll use for adding tie-outs I’ll decide later – I have a selection and will see what works best. Plus I may want to use some of the wider grosgrain I have to bind edges between the side panels of the inner. The plan is to add LineLoks to the tieout points (including at the peak).

This inner will have the zips done properly, and my working assumption is that I’ll go for the inverted “T” arrangement, and plan in the seam allowances and panel sizes to attach them at the start rather than adding later and “cutting through”. (The easiest way to do this is to make a panel bigger on each side, cut where I want the zips, add the zips, re-measure the whole finished front panel, and trim it down to the desired final size.)

There is still a chance I might go for the sideways “V” zips of my first inner, albeit sewn better. I’ll decide whether it’ll be a No.3 or a No. 5 zipper later when I can play with all the materials together and see what seems to work best. Either way it will be standard coil zipper rather than Aquaguard waterproof zipper.

Zipper pulls will be double-sided and I’ll add two to the vertical zip, allowing an additional venting option at the top.

Thread will be from my remaining stock of Gutermann Mara 70 in black, yellow or orange.

Next Time

In Part 2, I will go through the process of making the inner. But it’ll largely be similar to the original one, but with the modifications to approach for zips and corner stiffening I’ve already mentioned.

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