Strathcona Pack
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After a few years of jealously reading others MYOG pack projects, I decided to join the fray and try pack construction. The thought of having exactly what I want in a pack is a compelling proposition, even if the journey is difficult. The result is the 16oz Strathcona pack shown above.
Concept
I chose to construct a simple alpine style pack suitable for short solo backpacking trips and alpine touring day trips. My mind is full of imaginary packs, but I figured I should start simple due to my rudimentary sewing skills and lack of quality equipment (my flower decorated $50 sewing machine is Wal-Mart’s cheapest offering). Thus this pack lacks common features like side pockets, a front pocket and a frame.The inspirations for this pack are fairly obvious in the outcome. Dave C’s writings on pack construction, as well as his specific projects, served as the main sources of education and inspiration respectively. Also playing a seminal role was the work of Brendan and Aaron.
Skill limitations also shaped the design, most notably in the lack of side pockets. This summer on the PCT I was mulling aspects of pack design such as strapping water bottles to the shoulder straps a la ULA. This system has drawbacks, but it does move the center of mass forward slightly, and more importantly it’s much easier to construct.
Conversely, the lack of a frame was not due to fear (stay sleeves are easy) but to reduce overlap with the rest of my quiver of packs (ULA Ohm, ULA Catalyst). I wanted a pack that was smaller and lighter than my 24oz Ohm.
Measurements
Back panel: 10.5” wide
Front panel: 7” at bottom tapering to 10” at the top
Side panels: 6.5”
Extension collar: 9.5”
Torso: 20”Materials
Xpac VX42: Back, bottom (everything black minus shoulder straps)
Xpac VX21: Sides, front, extension collar
70D Nylon: Pad sleeve
1” webbing: Hipbelt
3/4” webbing: Compression straps, top strap
5/8” webbing: Shoulder strap daisy’s, sternum strap
1/2" webbing: Front panel daisy’s
Shoulder Straps: VX21 Pre-made by Chris ZimmerConstruction
Before I started on the actual pack construction I decided to make a feature-less dummy pack to practice sewing the tough spots (angled shoulder strap attachment, rounded bottom) and to confirm that I had chosen good dimensions. The ended up being a really good idea, as the tyvek dummy pack was badly misproportioned although easier to sew than expected. The final pack is 2" larger in circumference and with an extra 3" of torso length.For the real pack, I cut out all the main pieces and sewed on all the extra bits. To reduce the risk of mistakes, I first cut a template (not shown) for all the parts out of cardstock, drew all the straps etc on that and then traced/transferred the design to the actual material. The except to this is the shoulder straps. I wanted daisy chains so I could add a sternum strap and bungee cord for water bottles and there was no way my cheapo sewing machine could bartack through foam.
Sewing an angled, felled seam for the shoulder straps is the crux move and it occurs early on. To sew shoulder straps on an angle just cut out the matching pieces, snip the seam allowance perpendicularly on the upper piece (not possible to join the seams otherwise) and then once the 2 pieces are joined you can roll/fell the seam upwards which covers where you slit the upper seam allowance. This move worked perfectly on the dummy pack, but there's a bit of a wrinkle on the real pack mostly because my machine was struggling so much with all the fabric. The outcome is angled shoulder straps rolled into a flat felled seam such that the straps are bartacked to 5 layers of VX42. Yes beefy. My sewing machine agrees; I broke 3 needles sewing this seam.
The other difficult thing to conceptualize and sew is the curved bottom. There’s not really any special tricks here, just patience and slow progress. I first sewed the VX21 front of the pack to the VX42 bottom/back via felled seam. Then I sewed the sides in place. To sew in the sides, I did both the front and back straight seams first before tackling the curved bottom. This way the fabric is held roughly in place. Perhaps harder than sewing this is conceptualizing the pieces of fabric you need. I drew a rectangle side panel onto the cardstock (6.5” x 22”) and then free handed the bottom curve. Then I measured the length of this curve with some string, which told me how long I needed the edge of the bottom panel to be. As a margin of safety, I used huge 1" seam margins for everything and then trimmed that to 1/2" once the seam was sewn.
The rest of the construction is pretty straight forward. The hardest part is just not forgetting to put a strap in the seam at the right place. I added bias tape to finish the non-felled internal seams.
Features & Application
The dual compression straps aren’t really intended for compression, but for carrying skis and for mounting the pack to the bow of my packraft. The distance between the straps is based on my ski bindings. I wanted a third strap but my skis aren’t actually on my back that much.
Because I used buckles in the compression straps, I can rapidly affix this pack to my raft using male buckle halves already connected to my raft. This method is more parsimonious and solid than the complex webbing systems out there. The pack can be attached or detached in about 5 seconds.
Admittedly, the ½” webbing daisy chains on the front of the pack are about aesthetics as much as function. I don’t really need these, but they define the shape and there are a number of scenario’s where they could be valuable. I can zigzag shockcord to carry stuff externally (i.e. paddle blades, snowshoes, shovel blade, rain gear) and I’m also half planning to make a detachable pocket so I can carry smaller stuff externally.
This pack is also provisioned for carrying two ice axes, which I’ve never actually needed to do but the asymmetry of a single mount was intolerable. There's 1" velcro at the top of the daisy's and shockcord loops at the bottom. These should be handy for carrying trekking poles and packraft paddle sections. I can carry a section of paddle shaft on either side and then add shockcord to the daisy chains to secure the paddle blades.
I opted for a 1” webbing detachable hipbelt. For sub 20 lbs loads I prefer to carry the weight on my shoulders so this belt won’t be used much. Its purpose isn’t weight transfer, but rather to keep the pack from flying around while I’m skiing.
Looking inside the pack, there is a pad sleeve which is a bit poorly designed. I tried to come up with a clever sleeve that avoids the use of Velcro by having a little crack you insert the pad into. It might work, but the trouble is that when the pad is absent the pack isn’t stretched to it’s max width so the sleeve sags open and impairs loading of the pack. Perhaps this issue will be gone once the pad is added (I don’t have any suitable foam right now) but if not some modifications will be in store.
The end product weighs 15.8oz without the hipbelt and pad. It’s 16.8oz with the hipbelt (skiing mode) and my guess is +2oz once I find a suitable pad to add.
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