I've always wanted to longterm test a cuben fibre shelter but never really found anything I wanted to take on a long hike. Cuben fibre was supposed to be a wonder material that would transform lightweight hiking, but after having used it in many roles, ranging from packs to waterproofs, I've been somewhat underwhelmed. Perhaps shelters is where it really shines? My 2 previous cuben tarps didn't fare too well but a shaped tarp SHOULD work better. The difference here is that pegging/guying loads are spread, more evenly, around many more points, which could make a big difference. I already have an MLD Cricket, in cuben, but it's not nearly as flexible as the silnylon version, which I prefer, so I've hardly used it. I looked at a cuben Trailstar but the material has compromised the design so much that I didn't take the plunge. Zpacks make a nice cuben shelter called the Hexamid, and I got to look at many, up close, on the PCT. They looked ideal for that hike but the design puts weight above performance when the weather turns nasty, so again, I kept way. With a hike across New Zealand coming up I wanted a shelter suitable for more extreme conditions and decided I would build my own.
|Finished MYOG cuben shelter|
The design took shape in a 3D modelling program called Sketchup. This is a fantastic piece of software that is available for free if used for personal use. Took me about a day to figure out how to use it but it saved so much time overall that it was worth it. Available for Mac and PC I cannot recommend this software enough. From there I made a 1:10 scale paper model before committing to cuben to check if it all went together ok.
|Sketchup 3D model|
My design is heavily influenced by 2 of my favourite shelters which I have already mentioned, the MLD Cricket and Trailstar. The rear of my design has the shallow angles from the Trailstar and a 2-part, apexed, rear panel rather than a single, steep, flat panel like is the norm with a shelter like this (see MLD Cricket for an example). The shallow, apexed rear, is much better at deflecting wind which is the weak spot with the Cricket. To further reduce the angle of the rear panel, without increasing the footprint, I've moved the pole forward and placed it vertical, rather than offset.
|Forward, vertical, pole allows for better wind performance without an increase in footprint|
|Apexed rear allows for better wind resistant|
I've always liked the beak from the Hexamid more than what is fitted to the cuben Cricket. The cuben Cricket has a high, open, beak which is fine in good weather but on a shelter designed for wind and rain you want a lower, more protective, beak.
|Low beak provides rain protection|
A high, open, beak can be useful in warmer weather though so I made mine moveable. It can go from fully extended (above), to retracted (below), and anywhere in between. All this without touching the front guy.
|Beak fully retracted|
|Beak 1/2 retracted|
The beak is moved independently of the front guy so can be extended/retracted in seconds. It operates on a line-loc system with the main guy passing through a loop on the beak and up to a mounting point near the peak. A second guy is attached to a plastic loop on the beak end and passed through a second loop, on the main guy, and up through the peak loop and finally to a line-loc. Move the line-loc and the beak moves too. This all sounds complicated but hopefully you can see how it works from the photo's.
|Beak guying system partially retracted|
|Beak guying system fully extended|
I've also added a compact pitch option which brings the normally apexed rear panel in flat, and lowers the beak. This is useful for pitching in tight spots, say, a forest. A large footprint is normally the problem with shelters built for more extreme conditions but this shelter overcomes that. Performance is reduced of course so you would not pitch like this in an exposed spot, but it's fine for the intended forest pitch.
|Compact pitch option brings the rear in flat and lowers the beak|
Cuben's big weakness is that it has no stretch in the fabric, unlike silnylon, so trying to make a shelter pitch differently to how it was designed is difficult. Any attempt to alter the pitch normally ends in leftover fabric to flap in the wind. I had the same problem. Bringing the rear in of my shelter was easy. Just remove the centre rear stake and pull the 2 corners out tight. Fold the leftover panel under the shelter and attach to the internal clip.
|Rear folded and clipped out of the way in compact pitch|
|Apex stake point attaches to a clip when in compact pitch|
Lowering the beak would leave excess fabric that would flap in the breeze. I overcame that with a length of shock-cord fitted in the beak apex that could take up this excess material when the beak is lowered. The beak is still full adjustable and can be retracted if needed.
|Shock-cord and toggle to tighten up the beak in compact pitch|
|Compact pitch with fully retracted beak allows it to fit in very tight spots|
Working with cuben is easy, but very time consuming, and requires slightly different methods of construction. I chose to sew and bond all seams and just bond any reinforcement panels. All seams are sewn with a flat-felled seam and a strip of 3cm cuben was then bonded over the outside of the seam for strength. 0.74oz cuben was chosen because it is still very light but contains more kevlar thread than the lighter 0.51oz that the Zpacks Hexamid uses.
|Flat-felled seams with cuben strip bonded on the exterior|
A dyneema dome was added inside and out to take the strain and abrasion from the pole. The inner dome was sewn into the flat-felled seams, before the cuben strips were added, and the outer dome was aligned perfectly with the inner and secured by a single stitch line, right round the dome. The inner seam was then sealed with sealant to stop any leaks. An upper guy attachment point is sewn into the beak seam and through the inner dyneema dome only.
|Outer dome attachment and upper guying point|
All pegging points are fitted with line-locs which are sewn into the flat-felled seam. These areas are also strengthened with a second layer of cuben, which is bonded. On the outside is a 3cm strip of bonded cuben which strengthens and waterproofs the seam.
|Lin-locs fitted at all pegging points|
Weight of the finished shelter is 271g and it needs 6 pegs which are not included in the weight. Guys are included though. If I was to do this again then I could save a little weight by fitting a smaller dome on the outside. The dyneema is noticeably heavy compared to cuben, which at 4oz/yd compared to 0.75oz/yd isn't surprising. However, making the dome smaller would make its alignment much harder. Your choice! I would also consider lowering the pitch height from 125-130cm down to 115-120cm so that I could angle the rear/side panels even more. Unfortunately I'm limited by my fixed length hiking poles though.