Introduction and History

In November 1990 the permanent system was installed by diamond drilling an inclined hole through the coastal bedrock to locate and protect a new seawater transducer. The 12.8 m long drill hole is lined with 32 mm ID low density polythene pipe with a stainless steel cage at the bottom which locates the pressure transducer 8.04 m below the Cape Roberts tide gauge bench mark (CRTGBM #1). At start up the system consisted of a Campbell CR10 Data logger (S/N 0004172) and Geokon vibrating wire transducer (25 psi, 4500 ALV, S/N 13131). On 27 November 1994 at 1700 NZST the replacement transducer (25 psi, 4500 ALV, S/N 14740) became operative with a different CR10 data logger and this equipment continued to function until refurbishment in 2002.