underwater life detector project with arduino

Hey i am new to Arduino, I am trying to figure out a way to transmit and receive data underwater. I did consider attaching a 433Hz RF transmitter to my Arduino however at this point i am looking into hydrophones. I would like the Arduino to communicate with my computer giving orientation, pressure and other readings so that i can view them on my computer and the transmitter which will be fixed on land.. The Arduino will be 30 ft from the surface. However this distance will increase as a result of the transmitter not being directly below the receiver. So i plan to transmit through at least 100 ft of water.I have to design the underwater life detector circuit that transmit signal from underwater through radio frequency to transmitter that is on land in proteus software and matlab gui with the proper diagram The project is about The search and rescue operations in recent several major disaster have shown that it is very urgent to find effective and efficient life detection techniques, especially, for marine disasters. Such a task is very challenging and difficult. In this project, based on a thorough study of underwater communication methods, existing marine search and locating devices, GPS and special antenna technique the student should work out new underwater search and locating strategy and method for life detection. It is expected that the method can be demonstrated practically. If anyone does have any suggession please.Thank you