A few years ago, I was on a kayaking trip with a former Royal Marine: he described his fourteen years of service as fourteen years of tactical camping. Given that mindset, it was only a matter of time before one of the best-known outdoor companies, Arc’Teryx, started making military-focussed material.
Most interestingly in their pack range are the Drypacks: structured, completely waterproof, swimmable packs, available in 25, 40 and 70l. Each pack features an oral inflation valve, which allows the wearer to adjust the level of buoyancy required to support the pack’s loaded weight and function, from fully deflated to allow for underwater use, to fully inflated to cause the pack to bob along behind, or under, the wearer. This is obviously a boon to the military swimmer, but also the open water swimmer. No longer does an open water swimmer have to rely on a small float bag to put possessions in: they can now be kept close at hand, self-supporting as they go.
I have swim with both the 40 and the 25l variants: the former can be towed behind the swimmer via a waist tether, but the latter is small enough to comfortably wear as a backpack whilst swimming front crawl, without obstructing arm movement. With the buoyancy adjusted correctly, it’ll support its contents, without supporting the wearer, and provide a place to rest in the event of exhaustion. Should further inflation be required, the pack can be topped up with the oral inflation valve.
Inside, it’s brilliantly white, which makes being able to see anything inside is easy. There’s a small zip pocket (Tweave, I think), as well as velcro loop along the back of the pack with standard daisy chains along the side of the velcro.
Outside, the pack is smooth, with PALS loops LASER-cut into it. This makes a good, if somewhat nausea-inducing mount for a GoPro, or anything else you don’t mind getting wet. Perhaps a marker light, water bottle holder (with bottle), or hydration bladder holder (with bladder).