There are various options open to you to keep the items in your rucksack dry.

Firstly a wet rucksack is a heavy rucksack. Let alone the wet contents adding to this total. Covers are small and light, need to be able to completely surround you bag and any attachments, and it can be used to cover other things at camp. They work really well.

Rucksack liners are the next line of defence and you can use these without a cover. The older non roll-top type, are nowhere near as effective as the new ones. Depending on your personal preference you may wish to have one bag holding everything in you rucksack and/or several medium sized ones for each item(s).

However this latter approach tends to leave a lot of wasted ‘air’ space in the sack. Some people use bin or plastic bags, but these rip, and are environmentally unsound. Personally I use a combination of waterproof smaller bags, squashed flat, keeping the important things dry (sleeping bag, clothes) and a rucksack cover.