Thanks Sub Culture!
I did have "speaks" with Eagletree some years back and they were not certain it would work. Typically the Pitot tube has to be free of any flow disturbances which is why they mount the tube in front of the wing on airplanes. Just to give you a smile, some of the airplane guys have mounted the sensor almost behind the airplanes prop which gives a much higher indicated air speed! If I understand the physics involved, speed is a function of incomming pressure on a sensor compared to static pressure? It would seem to me that if you have your depth sensor in an area where there is no "flow" (static water pressure) and then compare this to incomming pressure you should be able to calculate the speed? Again I do not know enough about fluid flow characteristics. I did build a "venturi" type sensor however there did not seem to be enough pressure to get any readings. At http://www.flowmeters.com/
they show various types of flow meters. Maybe my research abilties with Google are not very good as I would think with all the RC speed boats someone would have built a speed sensor? I very much appreciate being able to discuss this with all the wonderful people here.