So I was doing some research and I found a new APP out for the iphone that lets you control the volume based on speed. I setup a separate profile for surfing and wakeboarding and so far it works awesome. Slow the boat down and the volume drops to a pre-set level, speed up above a certain speed and it raises up to a louder volume that you set. Very easy to use and only $.99. The speeds are pre-set so using the km instead of miles works a bit better because surf speeds are so close to 10mph and wake speeds are close to 20mph, so I set them to turn up at 10km and 20km instead. A decent use of a buck! The app is called Vol Adjuter (I think it's actually a spelling mistake). ONLY drawback is you have to use Bluetooth or the headphone jack, you can't use the outputs from an ipod cable. I added Bluetooth in my boat so this is perfect for us. Here is a link.