I was in Luleå for a week and saw in the local newspaper (nestled amidst nail-biting news stories such as ‘Local boy almost injured diving into river’) a poll which asked ‘Do you look forward to the return of Winter?’ (74% saying no). After a week of involuntary blood donations to the Luleå mosquito scene, I was a definite yes. I don’t miss a lot of things about Ireland, but one thing I miss is the near-total lack of winged, biting, blood-sucking insects. Even the Irish horseflies are tiny little midgets compared to the giant armour-plated Swedish bastards.


A tent will keep mosquitos away, but I don’t usually carry one. Tents are great at high altitudes, or when the temperatures go too low, or if your delicate fiancé has been dragged (literally, kicking and screaming) along. If possible though, I prefer to sleep just in a sleeping bag by the fire, draping a tarp or a waterproof jacket over me if it rains a little. During mosquito season this is pure masochism. The occasional bites would be bearable, but mosquitos seem to specialise in flying right into my ear and buzzing me awake every twenty minutes.
Recently during a particularly hellish, hot, humid, drizzling, mosquito-ridden, unending night, I was kept awake for hours by mosquitos suicide bombing my ears, and spent every minute fantasising about the most perfect bivy of all time. Something light-weight, lots of ventilation and totally bug-proof.  By the time the morning came and the mosquitos left me (taking with them around a litre of my blood, of which I am very fond), I had become totally fixated on the idea of making my own bivy.

So I ordered a load of materials from This site is completely fantastic, they offer dozens of great textiles, from reliable old nylon to magical kevlar. Connectors, zippers, cords, slings, carabiners, insulation, they have it. Nice customer service and fast delivery too.

My plan is to first make a simple rope tarp for climbing to get some practise. Rope tarps are just big squares of material to stand on and have your rope on when you climb, keeping the dirt off the rope and off the bottom of your expensive climbing shoes. I’m not sure how much work there will be in turning a one metre long square of nylon into a one metre long square nylon tarp, but I’m sure I’ll find some way to screw it up.

If that goes well I’ll try to sew up a bivy. Hopefully something under half a kilo, with decent breathability for these hot Summer nights. It seems a lot more fun and rewarding than just buying something, as well as being a learning experience.

A close-up of the lovely aramid reinforced X-pac material. a very tough nylon for the rope tarp.
A tubular sling from Edelrid, takes 1835 Kg at 35 g/m. It would be nice to have some tie-in points on the tarp, so I will try and use the sling for that.
Two cords looped through the micro carabiner from Edelrid. The cord on the left is 3mm Dyneema/Polyester, takes 420 daN. The grey cord on the right is 1.5 mm pure Dyneema, and takes 220 daN.


The carabiner is ridiculously well made. It’s tiny, weights 3.7 g and can take 150 kg on the major axis. Obviously not for climbing, but useful nonetheless.

Some light (50 gr/m^2) green siliconised nylon ripstop in the back, and some delicious mosquito netting (155 meshes per cm^2) in front.

Some other assorted goodies, a waterproof zip, some seam sealer and a metre of breathable fabric.

Now all this project needs is a little bit of careful planning and patience. Neither of which I am remotely capable of supplying, so instead I’ll just give it a shot and see what happens. Things usually work out quite well that way.

4 thoughts on “MYOG

  • July 25, 2010 at 10:25 am

    Tomas, you should be able to make a bug proof, highly breathable bivy for well under 'half a kilo'. My Katabatic Bristlecone bivy, with waterproof sil-nylon floor, highly breathable, water resistant top, bug net and side zip weighs in at 205g in the Large size. Under a 300g tarp I have a totally waterproof but highly breathable, bug proof shelter with enough room for two people!

    Tyvek is another good material for MYOG projects. Check out Hamilton's Tyvek bivy here:

  • July 26, 2010 at 9:14 am


    I totally advocate the 'just give it a shot' approach! It's more fun that way.

    I'm still fantasizing about the perfect bivy, and after I take the current super simple MYOG out for a big hike, I'm sure I'll be eager to improve upon it.

    Keep us updated! Can't wait to see what you come up with.

  • July 26, 2010 at 5:25 pm

    Thanks for the feedback guys!

    Not sure Tyvek is waterproof enough, I plan to use this bivy for a lot of climbing/kayaking trips, so probably won't be able to use a tarp all the time. But you're right that I should be able to get it well under half a kilo, I should put some pressure on myself and aim for something under 300 grammes!

  • February 18, 2016 at 9:00 am

    As an UL backpacker, I have used this bivvy in place of a slpeeing bag inside a Big Agnes Fly Creek UL1 tent, slpeeing on an insulted air slpeeing pad with Smartwool sleepwear, fleece hat and socks. I have taken it down to the high 40s comfortably. My only concerns were breathability and reflectivity of warmth, both were excellent even during an all-night rain storm. I can probably take it down to lower temps wearing a down jacket, thicker fleece leggings, balaclava and slpeeing with a hot water bottle. The clothes are not extra weight in my pack as I always bring them on a winter backpacking trip.


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