There's a nice discussion of the problem here
. Absorption by fresh water at 2.3 GHz is 194 dB/m! (using their formula). That's 2dB/cm. 3dB is a factor of 2 signal strength loss. After about 5cm your signal is 1/10th its original strength. And there is interface loss at the surface, plus the change in wavelength in water which will make your for-air designed receiving antenna less efficient. Your best bet may be to shave and tape on some wires.