Lightweight backpack

Drybag top. The original design had a simple draw cord cinch closure, which you can roll down and tuck under the compression strap. I found this very difficult to close in such a way that it would keep the rain out, so I decided to make a larger version of a drybag-style closure: A hemmed top stiffened with flexible plastic, with webbing sewn along one side, fastened with a side release buckle. I studied one of my Exped drybags and reverse-engineered their design on a larger scale.

Hipbelt. Scrambling with a heavy pack is a little tricky. Having had a few hairy moments on Great Gable and Striding Edge, I knew I needed the extra security of a hipbelt. Not for weight distribution, but to keep the pack steady on my back. This is less of an issue if you’re only walking on level ground. I also added simple mesh pockets to the hipbelt, because they’re so useful. Nothing too big, but roomy enough to hold a compass or a chocolate bar.

Mesh side pockets. I wanted big side packets to store stuff in. A large external mesh pocket on the front is also useful for carrying a wet tent or clothes.

Better compression. Jay’s design has an ingeniously economical compression system. But I wanted something a little more robust, and also one that could double up as an attachment system for wet gear. Using this system, I can strap my whole Laser Competition tent down one side of the pack. I also added loads of extra grosgrain loops for more compression cord or as attachment points, since there is so little weight, strength or cost penalty.

Internal sleeve for pack padding. My design uses a piece of closed cell foam as back padding and for better weight distribution. It’s an experiment, but I figured it would be easy to do, and the foam is removable, so I can always dispense with it if it doesn’t work out. I could also use the small piece of foam as part of sleeping pad system if I end up getting a smaller 3/4-length sleeping pad in the future.

It’s black. In the Hitch Hikers Guide to the Galaxy, Zaphod Beeblebrox and Ford Prefect steal a spaceship from Milliways, the Restaurant at the End of the Universe. Zaphod comments on the control panel:

It’s the weird colour scheme that freaks me. Every time you try to operate one of these weird black controls, which are labeled in black on a black background, a small black light lights up black to let you know you’ve done it. Hey, what is this, some kind of galactic hyper-hearse?

’nuff said.

1. Cut the pocket fabric: a piece of mesh fabric 10cm wider and 5cm taller than the size you want your pockets to be. I gave mine a slanted top as well to make them easier to access while wearing the pack.
2. Make the shockcord-elasticated top. Cut two pieces of 15mm grosgrain and sew them on to the top of the pocket fabric, sandwiching the fabric between the two. Or use one piece of 30mm grosgrain and fold it over, again with the fabric sandwiched between. Thread a piece of shockcord through the channel you’ve just made.
3. With a needle and thread, sew a running stitch around the other 3 sides of the pocket. As you finish each side, pull the thread to bunch up the pocket fabric (like drawing a curtain). When you have bunched up the fabric to the correct size, secure your running stitch at the corner with a knot or a loop.
4. You can then baste each pocket onto the main pack side panels. The exposed edges will be sewn into the main seams of the pack. When sewing up the tops of each side (the shockcord channel) pull the shockcord tight, so it sits flush against the main pack side panel. The shockcord channel should be bunched up when the pocket is flat against the pack so it has room to expand when you use the pocket.

It’s worth considering how much extra fabric you want to give the pockets. I added 10cm width to each of the side pockets, but only 5cm to the back pocket. I thought that I would need less room in this pocket. In practice, I could have done with more — the back pocket isn’t roomy enough, and the space that 5cm of extra fabric gives is quickly swallowed up when the main pack is full.

1. Start by trimming the top edge so it’s even all the way round.
2. Cut a piece of 20mm webbing with a length of half the circumference of the pack + an 10cm (to allow for the side release buckles)
3. Cut two strips of flexible plastic; one the width of the webbing (20mm), one a bit narrower (say, 15mm). The first should be about 1cm less than half the circumference of the pack, the second about 2 cm less.
4. Roll each piece into the top edge of the pack with 2 folds and pin, before sewing along the bottom fold to form a seam with the plastic sealed inside.
5. Thread the webbing through each half of the buckle – one half at each end. Fold the webbing over at each end and stitch across its width close to each buckle.
6. Place the webbing on the pack on the side with the shorter, thinner plastic. It should protrude about an inch from either side. Stitch the webbing onto the pack by sewing all the way round, close to the edge of the webbing, and through the pack fabric, but missing the plastic. (That’s why this piece of plastic is slightly smaller.)

Main compression strap. My pack has a compression strap that is sewn into the front bottom hem, is attached to the front mesh packet, clips above that, and continues over the roll top closure into the seam along the top back where the shoulder straps are attached. So far, I’m pretty pleased with how well this works. But it’s tricky to make, because you have to get the sewing order right.

1. When making the front pocket, sew on the grosgrain channel to the front of the mesh fabric. I used two pieces of 15mm grosgrain, but this would be a lot easier with one piece of 30mm folded over.
2. Cut a piece of webbing for the compression strap. It should be long enough to allow for plenty of height adjustment. I’d say mine is about 80cm long.
3. Sew the webbing up the front of the pocket, stopping when you get about 2/5 of the way up the grosgrain.
4. Flip the assembly over so the webbing is on the table, followed by the grosgrain, then the mesh fabric
5. Place the shockcord along the grosgrain, and fold it over to form a channel with the shockcord inside (or in my case, place on top another piece of grosgrain. This is when it becomes obvious why you have to stop sewing less than halfway up the grosgrain – you don’t want the webbing strap to fold over when you make the channel.
6. Sew up the grosgrain channel to seal in the shockcord. Once, along the bottom, if you’re using one wide piece folded over. Or twice, along the top and bottom, if you’re using two pieces of half the width. This is when it becomes obvious why you have to sew the webbing strap on first. If you were to do it now, you’d end up stitching through the shockcord, preventing its free movement.
7. When you’ve finished the main pack construction, you can attach the side release buckle to this strap. Fit the adjustable half of the buckle to the front strap, and the fixed half to the rear strap that comes over the top of the pack. The strap will be loose in this half of the buckle, but eventually you will sew it in to a fixed position.
8. Fill the pack to it’s smallest likely level, tighten the adjustable buckle, clip it to the other half of the buckle and pull the rear strap through until the pack is compressed.
9. Pin the rear strap to fix its position in the buckle.
10. Then fill the pack up some more, to it’s highest likely level, close it, loosen the adjustable strap at the front, clip the buckle closed to verify that your strap is long enough. The picture shows my pack at this stage.
11. When you’re happy that your strap is adjustable within the limits you’ll need, you can sew the non-adjustable half of the buckle onto the rear strap and trim the excess webbing.

Padded hipbelt. This has a complex construction, with two layers of fabric, an internal webbing strap, foam padding and a mesh pocket. The two halves had to be made inside out, then the short ends sealed (with the webbing strap protruding, not trapped inside the pocket), then the padding fitted inside, then sealed at the long end.

I made a tissue paper prototype first to figure out the right way to layer the fabrics. It saved me a lot of wasted time and fabric.

Shoulder straps. I copied the simple shoulder straps from Jay’s original design. But when I took the pack out for it’s first test run, I found the straps were too close together, and dug into my neck and trapezius muscles. To be fair, I was carrying a very heavy load by ‘lightweight’ standards (probably something like 15kg, which is really too much for a frameless pack). But the discomfort was noticeable after a few minutes, so even with a lighter load, I’d be feeling the pinch — literally — on a 2-day trip. On a heavier framed pack, this would be less of a problem, but my frameless pack deformed significantly under the load, in a way that I had not expected. After all my work, this was something of a low point.

So I unpicked the seams along the back of the pack, and a few centimetres down each side, and unpicked the shoulder straps. I repositioned them further apart ], pinned them in place and tested the pack out again. When I was satisfied with the positioning, I sewed it all back up. This whole process was surprisingly easy, once I’d recovered from the initial trauma of having made such a serious mistake.

So far, this new arrangement seems comfortable enough, but in future, I’ll probably look at making curved shoulder straps to lessen this problem. It’s clear that careful consideration needs to be given to the physical behaviour of the pack under typical loads, as it can deform significantly.