If you're looking for a good alternative to your phone as a camera, do an amazon search for action camera. There are so many good options at a fraction of the cost of a gopro. Most of them even use the same mount and accessories. Most come with a huge kit of mounts, an extra battery on some and the video quality is great! Try and find one that has image stabilization and will run at at least 60 fps at 720p, if not higher. At the price they go for, heck, you could buy 6 and strap one to each buoy!