The Encyclopedia of Earth says “We live on a planet that is dominated by water. More than 70% of the Earth’s surface is covered with this simple molecule.” On any trip, millions of water molecules are trying to find their way into your phone, your camera, your lunch, and onto your map and towel.
Kayak manufacturers have made many attempts to create 100% waterproof compartments in their boats but so far they have been largely unsuccessful. With necessity being the mother of invention, many containers, cases, and bags have been developed as solutions to the problem. It is a good idea to use a combination of these in various sizes rather than just one big one. This is because each time you open a bag to retrieve a particular item the remaining gear inside is exposed.
A one litre dry bag works well. Some people use a plastic jar, like a peanut butter jar. Just make sure that it’s watertight.
There are many cases sized specifically for phones that have at least one clear side so you can make and receive calls without having to open them.
It is possible to get waterproof map cases that are clear on both sides so you can use your maps and guides without worrying about ruining them.
Towel and food
These can often be combined in the same dry bag because you usually get them out at the same time.
First aid kit and spare clothes
As emergency items, these should be kept in their own ten to twenty litre dry bag.