Water is a great enemy of all our things, especially electronics. Other things can also make the situation uncomfortable when they get soaked. For example, during our multi-day trips we will carry extra clothes and if it gets wet we have nothing to wear. Even if we can not avoid such a "disaster", we can still prevent it. This applies especially to water sports along with dry clothes and equipment.
They are everywhere
Even with sports such as yachting, rafting etc., we will need a space to store our things. This space will be of course some kind of backpack, but what if it gets wet ? Our things will naturally get wet too and electronics may be irreversibly damaged. Would we believe that such troubles can be avoided? Dry bags are perfectly adapted to this. We can say that any backpack can serve well, but there is a huge difference.
It simply is true
Generally drybags are like standard backpacks. They also have shoulder straps, some type of carrying system, etc. The fact that it is actually a drybag should be mentioned in the description of the product. What criteria should such a bag have ? Of course it should be 100 % waterproof. In the end, they are designed for water activities. The other features are already secondary. Their waterproofness is ensured by the material used. In most of the cases it is 100% PVC. When choosing a backpack, pay attention to both the material and the connecting components. Sewn seams are really inappropriate, they must be glued or combined. By these components, we mean zippers, velcro, etc. and even those must be waterproof. But how do we get inside ?
Roll, roll, roll....
Closing the main compartment is a bit of a challenge due to the desired waterproofness. The top is usually high with either zipper or velcro closure. After closing, we roll it until we can extra fasten it by a strap with buckle. This method is highly reliable and essential when choosing a backpack. After this (making sure that all the water stays out), which really is the most important thing, we can then focus on carrying system, shoulder straps, extra pockets, etc. These features are also important if we want not only functional, but also well designed bag. Here, however, the opinions are different, as everyone has a different idea of what they need.