The Lagrangian Drifter

The drifter concept relies on the variable buoyancy control of this system to allow the vehicle to hold its position within the water column at pre determined depths as opposed to the typical descent and crash land of current landers. The advantage of 'drifting' rather than using, for example, a remotely operated vehicle (ROV) is that it minimises biological avoidance in the absence of thruster propulsion, hydrodynamic disturbance and powerful lighting. The drifter would be able to silently drift into schools of midwater fish, squid or plankton recording data using either sonar or low/red light camera techniques (no need for intense powerful lights when not piloting in real time).

The variable buoyancy unit could also be used to decelerate the lander on approach and possibly achieve an impact force of close to 0kg, and once landed, add the remaining 25kg weight back aiding instrument penetration and holding stability.

The variable buoyancy control could also allow a lander to land on one site, take its measurements (e.g. photography, benthic respiration, corers etc), ascend into the water column and be transported to a new site by the currents and land again. This would allow the lander to gather data from multiple sites from the same deployment, minimising the amount of expensive ship time.

Contact

Dr Phil Bagley, Oceanlab Manager/Senior Engineer
Telephone: +44 (0)1224 27441
Email: p.bagley@abdn.ac.uk