Report: Arnold, SE. 1971. Cruise Report for MV Moray Firth IV North Irish Sea Survey. MGU Project 69/02. (IGS Report No 17) Positioning: Main Chain Decca with Mark12 receiver Echo Sounding: Kelvin Hughes MS 36 and MS32 Sonar Systems: EG&G side-scan sonar Kelvin Hughes MS43 Mk1 transit sonar Seismic Systems: Sparker System: EG&G sparker system with 16 element hydrophone streamer. Most lines run at either 0.5kJ or 3kJ Magnetometer: Varian magnetometer. See also IGS report 71/19.