I am enthusiastic over humanity’s extraordinary and sometimes very timely ingenuity. If you are in a shipwreck and all the boats are gone, a piano top buoyant enough to keep you afloat that comes along makes a fortuitous life preserver. But this is not to say that the best way to design a life preserver is in the form of a piano top. I think that we are clinging to a great many piano tops in accepting yesterday’s fortuitous contrivings as constituting the only means for solving a given problem.
― R. Buckminster Fuller
As product designers, we get to live in a world of "what if": we look at how things are, and we get to imagine new ways they could be. We analyze existing tools, processes, features, and functionalities. We ask "what works?" and "how can it work even better?" And then (Tom likes this part best), we go out to the workshop and make some prototype bags. We take them on the trail, on a road trip, or a plane ride. We use the bags in situ to see if we're headed in the right direction.
Sometimes our best design is but a chimera: what is called for is some sort of "Klein Bottle" (or perhaps a Klein Bag?)—something we can imagine but no one can actually make. Sometimes we suffer from what Tom calls "Kevenhüller Syndrome" (from Selma Lagerlöf's Gösta Berling's Saga): maybe we can make one of something, but it turns out to be impossible to mass-produce. At the end of the day, we are not simply product designers, we are manufacturers as well. We must create things that can be imagined and then manufactured.
Like other kinds of birthing, taking a nascent idea for a bag and turning it into a finished thing can be messy. We put lots of thought into what features are truly essential for a particular design, and what features are extraneous. We try to be thoughtful, careful, and conservative. And when we release a new bag, we then listen closely to the feedback we get: are people liking it? Are they using it as we intended, or have they hacked it to do something we didn't even know was possible? We realize we can't please everyone, but we try to see how close we came to hitting our mark.
Do we get it right every time? Certainly not, so we often continue tweaking, refining, and fine tuning our designs, sometimes forever. In the design process, we challenge ourselves with some tough decisions: sometimes, adding a feature or a specific functionality would detract from some other utilization, or add substantial or unjustified weight, bulk, or cost, so we might forego it. Sometimes there might be several good ways to achieve a certain utility or aesthetic, and we must choose between them. It's a fun challenge, and we're glad you've come along for the ride.
The top pocket of The Guide's Pack is great example of such a challenge. It acts primarily as a flap that covers the drawstring opening, protecting the contents of the main compartment from the weather. The pocket is designed with a zipper along what we think of as its "front" edge, where it is convenient to access when you're not wearing the pack. However, the orientation of the pocket, and therefore the relative position of the zipper on the pocket, varies depending upon how full the main compartment is or isn't.
When the main compartment is empty or not very full, the pocket—or flap, if you prefer—will swing down, sloping away from the wearer's back, its front edge coming to rest lower than the rest of the pocket. Thus, when the main compartment is less than full, the front zipper is indeed effectively at the "bottom" of the top pocket.
When the main compartment is full, the pocket is more or less level and the zipper is now at the front edge of the pocket. And when the main compartment is more than full, or if something is stuffed under the pocket, atop the main compartment's drawstring top, the pocket will swing upwards and the same zipper opening that was previously at the bottom of the pocket is now at the top of the pocket. It's important for the sake of this discussion to note that in all these orientations, the weather flap that covers the pocket zipper is still doing its job of protecting the zipper from rain/weather.
It is somewhat counter-intuitive (and yes, sometimes down-right inconvenient) that this zipper is at times at the bottom of the pocket. The only way around this would be to move the zipper to the opposite edge of the top pocket, the edge that would be the "top" when the bag is less than fully-loaded. Though this might be an obvious "solution" to this design challenge, placing the zipper on that other edge of the pocket just reverses the whole thing: now the zipper is at the bottom of the pocket when the bag is over-loaded. Plus it creates yet another challenge: if you're going to put a weather flap on the pocket's zipper (which the aesthetics and functionality of the Guide's Pack dictate), then you must decide which way that flap goes. In one orientation, the flap will protect the zipper from rain and weather when the bag is empty (or nearly so) but will actively channel water into the zipper when the bag is full or over-full. Flip the zipper flap the other way, and the choice is simply reversed: weather-proof when full, the opposite of weather-proof when empty.
This is a good example of the trade-offs that designers often need to consider. When we were looking at vintage backpacks that were the stylistic roots of the Guide's Pack, that top pocket zipper placement was done both ways. We choose weather-proofness over the inconvenience of the sometimes "upside down" pocket zipper.
Note that Tom uses the Guide's Pack several times a week. He says, "Yup, that zipper placement on that top pocket is a compromise, all right. But it's the best compromise in my opinion."