As we made our way upstream, the gorge changed from a wide valley into... well, a gorge. Not far beyond this point we ran out of bank, which meant we were in for an impromptu swim. We had always assumed that some parts of the walk would involve floating our packs and swimming with them, but I don't think anyone expected it to happen right here. The trick with floating your pack is to line it inside with a large drybag or 2 tough plastic bags, and pack your gear inside that. Float the pack with the harness side up. Even a heavy pack will float with more than half of it above the waterline.