Preparing for hydrographic survey Marlborough Sounds

iXblue is excited to have commenced preparations last week for a new survey project in New Zealand, which we’ll be undertaking with several local partners including Discovery Marine Limited (DML) and NIWA.

It’s a joint hydrographic survey project between Land Information New Zealand (LINZ) and the Marlborough District Council (MDC), and will take place in the picturesque Western Marlborough Sounds region over the NZ summer.

In addition to being one of the most scenic waterways in all of New Zealand, it is also an important marine resource for the aquaculture industry, being home to a large number of scallop farms.  Accordingly, the survey will deliver against two key aims.

  1. It will provide data to allow LINZ to update the bathymetry contained on the nautical charts for the region, which will in turn ensure the navigational safety of mariners.
  2. It will also provide a basis for future marine science in the region and help inform policy decisions for the aquaculture industry.

The equipment choices for the survey

Local survey vessel

We’ve chartered a shallow draft survey vessel from NZ based firm Pacific 7 Limited.  Pacific 7 has extensive experience operating survey vessels in and around the NZ coastline and were an obvious choice for the role.

The very latest echosounder and our custom designed fairing

Konsberg Em2040 Multibeam echosounder

The survey area has a high percentage of shallow water, so a dual-head system is being fitted to maximise the seafloor coverage and deliver a high rate of effort in a timely manner.  We’re using a new Kongsberg Em2040 Multibeam echosounder, the latest and highest specification shallow water system currently offered by Kongsberg.

As with any acoustic sensor, it is always preferable to minimise the flow of turbulent water across the face of the sonar and to reduce the inherent drag and vibration on the pole that secures the sonar to the vessel.

The Em2040 system is considerably larger than the Em2040 Compact system we’ve used in the past, so we decided to experiment and build an over-the-side mount that offers a low drag, hydrodynamic design.

Our survey engineer Jared Smith had a lot of fun working with a local industrial designer to come up with a fairing design which could meet these two basic requirements.  After several hours of debate and a little CFD analysis of the design, within just a few weeks a local machine shop had brought the 3D CAD drawing to life.  A lick of red paint, and the new fairing was good to go.

Em2040 Multibeam echosounder fairing

We have continued our usual practice of fitting and using the Valeport MiniSVS sound velocity sensor for this installation.  The SVS sensor has been fitted in the tail section of the mount and provides real time, high quality sound velocity information to the sonar.

Advanced navigation system

For the first time in many years, we are also using the iXblue HYDRINS Inertial Navigation System which will provide high quality altitude and positional data to the sonar system.  With this system, we doubt that money could buy a more technically advanced solution for this project.

Our team is very excited at the opportunity to be working in another remote but beautiful region of New Zealand and using the latest technology from Kongsberg, Valeport and iXblue.  We remain privileged to be working on projects such as these and cannot wait to get the mobilisation phase behind us so that we can make our way to site and get started with the survey.

David Donohue

As Managing Director David's role is to ensure clients' surveys are undertaken with precision and to meet budgets, schedules and relevant survey standards. His particular driving passion is innovation and process improvement.

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