wwbrown:
That you have made a number of related posts and this kind intrigues me, if you had read that the ultrasonic transceiver worked for your application based on a DIY ROV forum why do you ask here? It would seem that the ROV forum would have a higher IQ for your ROV application then this forum.Most of us have been in similar circumstances that you find yourself in and realize we are just going to have purchase the hardware required and try it out on our application and see if it works. R think you are at that point right now.
well i'm posting for the assurance that the item might or might not work, The item is not currently available in our country and the only way is to order outside our country, therefore, i must assure that this kind of sensor is feasible in my project and not to waste a considerable amount of money 
thank you for your humble reply sir...