I know that Bluetooth operating at the standard 2.4GHz has a hard time penetrating water (I guess the water "absorbs" the signal). However, at what depth does this really start? In my case I am thinking about a device that operates within 1 meter of the surface and would transmit to someone nearby on land. Is a reliable pairing possible to attain and maintain? If so, is it doable with standard transmitters? That is, would there need to be any special signal amplifiers or the like?
Furthermore, if this is possible, is it only possible with Bluetooth classic or would BLE fare similarly?