The Underwater Gamma Probe (UGP) is designed to measure gamma doserate or display counts over a predetermined time interval. The UGP comprises of an anodised aluminium housing, gm tube, signal processing electronics, data logger, power supply and RS485 communications circuitry. The UGP is capable of operating autonomously for a period of 100 hours or can be monitored remotely by means of a portable instrument (e.g. JCS NMS014) or optional handheld/personal computer (running the JCS Data Logging Application).