I love water crossings and incorporate them in my rides as much as possible. On hot days we actually head down to the swimming holes, strip the saddles , strip part of our clothes and head in for a swim. We use one stirrup leather from an english saddle around the neck to hold on to. I often use the tail, slide off his back as he goes deep and then just float back to the tail and steer him from there pulling myself back up on him as we start to hit shallow water.