Presently I am working on Underwater Acoustic Wireless Transmission. I desire to measure water parameters at the bottom of the surface of the water and then pass it to the water surface using Ultrasound. There will be a buoy at the surface which is half submerged and half floating. The floating part will have the receiver. Desired data rate is around several tens of kbps. What are various Transducers available for this purpose to make a prototype with Arduino? HC-SR 04 is the only easily available Ultrasound Transducer available at my place. But will it work underwater? Also suggest me good open source simulators which can satisfy this need?