Brazilian oceanographic consulting firm HidroMares has been using a Homer Pro underwater relocation system supplied by Sonardyne Brasil Ltd. as part of a currents and waves monitoring survey in Sepetiba Bay, Rio de Janeiro. Contracted by Odebrecht as part of a shipyard and naval base construction project for the Brazilian Navy, HidroMares is using Homer Pro to mark the position of the wave and current data, tide and temperature sensors deployed on the seabed to monitor environmental changes inside the bay as a result of the ongoing infrastructure development.
A Homer Pro system comprises a diver-held relocation device and marker transponders which are deployed at the target locations. For this project, the transponders were installed together with the sensor instruments in anti-trawl seabed frames deployed at four points inside the bay at depths ranging from 6 to 18 metres. Each transponder has a unique address code, enabling it to be accurately marked and relocated. When a diver wishes to locate a sensor frame marked with a particular transponder, he selects the address on the handheld unit which then sends out an interrogation signal. If in acoustic range, the selected transponder will automatically respond. The direction and distance to the transponder is displayed on the diver’s unit, allowing them to swim straight to it.
“We have been incredibly impressed and are exceptionally happy with the performance of the Homer Pro throughout this study. Our divers have reported that the system is easy to use and the fast, simple target location has meant we’ve been able to collect six months of data so far with minimal expense in terms of time and money spent on diving operations.”