Odim Brooke Ocean manufactures a wide array of oceanographic products, both platforms and instrumentation suites.  Product examples include the Moving Vessel Profiler, winch systems, the FFCP (Free Fall Cone Penetrometer), and the LOPC (Laser Optical Plankton Counter).  In 1997, Brooke approached Applied Microsystems for assistance in finding a solution for their need of both sound velocity and CTD instrumentation capable of withstanding the unique conditions and requirements of a Moving Vessel Profiler (MVP).

The primary intent of the MVP is to allow accurate profiling data collection without the need to stop the vessel.   The system was originally designed to collect sound velocity (SV) data for shallow hydrographic operations.  This sound velocity data was used to calibrate multi-beam sonar data for the Canadian Hydrographic Service.

There were three primary requirements in designing a suite of CTD and sound velocity instruments capable of working reliably on the Moving Vessel Profiler.  These were:

• The high speed of descent
• The dramatic G forces
• The fit between the instrument and the platform, both physical and in terms of data outputs

In order to propose an effective solution, Applied Microsystems needed to customize our sensors in order to meet all three of these requirements.  In the picture below, a customized Applied Microsystems sound velocity sensor is visible on the right hand side of the MVP, pointing downwards.

With descent speeds through the water column of up to 3.5 meters per second, several design related challenges were identified.  These challenges required solutions for MVP flow dynamics, data sampling rates and sensor response times.   AML resolved these challenges by developing sensor and electronic packages capable of dramatically higher sampling rates of up to 25 Hz with fast responding, flow independent sensors to enable data capture with high resolution.

To facilitate the physical mounting or placement of the instruments onboard the MVP’s free fall fish, special consideration was given to avoid boundary and flow induced noise while minimizing any drag caused from the sensor placement.   These constraints coupled with the requirements for increased ruggedness to stand up against the effects of high speed profiling and the G forces subjected to the instruments during the ascent transition, called for a custom mechanical design.
 
AML designed a custom housing and end cap for right angle sensor mounts to bring the sensors into the clear flow avoiding boundary and flow effects while embedding the housing inside the free fall fish for drag reduction.  Additional customization included a ruggedized temperature sensor and for some unique MVP applications a set of secondary support struts for the conductivity sensor.

Applied Microsystems delivered the first Micro SV&P prototype in 1997.  After fine tuning the original mechanical design and some custom modifications to the firmware for data integration, a CTD prototype was offered in 1998.

ODIM Brooke Ocean exclusively purchased the Micro CTD and Micro SVT&P for their Moving Vessel Profilers.  More recently, Applied Microsystems has collaborated on the integration of our SV and CTD products with the Odim Brooke Ocean LOPC and FFCP products.