In October last year I made my first audio recording of the Firth of Forth from a diving rib that was around 500-600 metres away from the main deep shipping channel. My hydrophone was at approximately 20 metres in depth and highlights that the attenuation of sound through water is extremely efficient. As I was making the recording, a large tanker appeared further up the estuary a couple of miles away, the noise of its engines slowly increasing until it was quite overpoweringly noisy. In this audio clip, the ship has reached a parallel point to our boat. The noise of the divers beneath us can still be heard in amongst the tanker noise, the intake breath is much like a sucking/hissing sound and the expelled air is like running water. HMS Saucy lies at the other side of this channel, which means that future recordings of this site will be problematic due to other environmental noise.