We always take float bags with us, both bow and stern. If we are touring they are deflated while we are completely loaded but can quickly be inflated to give added protection while doing a paddle after camp is set up. Also on longer trips we are able to fill the space that once contained food with backup buoyancy. Plus filling the void keeps cargo where we want it, low and in the middle of the boat.
Like Nhk said the new bags are quite airtight and very durable.
Sea Kayaker Magazine