MSI completes 'Deepest, Longest Moorings' to Date

In late 2018 Total contracted Metocean Services International (MSI) to mobilize what would be MSI's longest moorings for deployment in the deepest water to date (3,150m) at locations just north of the border between South Africa and Namibia.

The moorings comprise a surface buoy to measure meteorology, waves and current profiles as well as an I-type mooring to measure full water column current profiles and water quality.

Because the top of the I-type mooring needed to be near the surface, special attention was paid to the mooring design.
This was modeled using third party software to ensure that the instruments remain at their intended depths, taking into account the type of rope used for the mooring, as well as the expected metocean conditions on site.

Data from the surface buoy is being transmitted in real-time via the Inmarsat DataPro service where it is displayed on a password-protected website for the client to access.

Photo: MSI

This also allows MSI to monitor the status of the buoy, which also has automatic alerts configured if it moves outside a preset watch circle or if water intrusion is detected.

The initial deployment of the equipment was timed to coincide with an environmental baseline study (EBS) which was subcontracted by MSI to Benthic Solutions Ltd (BSL).

The dual scope of work meant that the vessel used, the OYA from ABC Maritime, had to be outfitted in Walvis Bay with an A-frame, winch and generator.

The EBS comprised sediment and water sampling, water quality measurements, seabed photography and video, passive acoustic monitoring (PAM) and marine mammal observations (MMO).

At the first of two interim service visits, conducted in April 2019, the I-type mooring was serviced and the vessel carried additional personnel from BSL to collect more PAM and MMO data.

At the second service visit both moorings were recovered and redeployed and MSI is now planning for the final demobilization of the project in November 2019.