OSV Mariska G: Modified for Seismic Operations

The Mariska G is an offshore supply vessel (OSV) belonging to Rederij Groen B.V., a Norwegian shipping company specialising in guard and seismic support vessel operations. The customer’s brief was to convert this newly acquired OSV into a robust platform that could support their seismic activities.

Class approval for the engineering concept was still pending when the vessel sailed into Tuas Yard on 6 January 2020. Nevertheless, having worked with the Marine team in ST Engineering on ship maintenance and repairs over the last two years, the customer had full confidence in our experience and capabilities. On our part, we were delighted to bring our deep knowledge on such conversions and similar experience with other seismic vessels to the fore.

The Marine team swung into action the moment Class approval was obtained on 16 January 2020. We had two months to complete the massive mission, which included the installation of a new fuel oil (FO) tank and bunkering system, as well as the streamer and hose reels required for the seismic support function.

According to Mr. Dirk Klok the Vessel Manager in ST Engineering Marine Ltd, who was responsible for Mariska G’s redelivery, meticulous planning was the secret to the team’s success. “The removal of existing cement tanks, fabrication and conversion of various tanks into FO tanks, as well as integration of the FO system interface with the ship system were among the complex engineering works involved in this contract. To achieve the modification works within the tight timeline, we anticipated the challenges, had the right resources on standby and were well prepared. It was all hands on deck for our crew.” He said.

The Mariska G was proudly redelivered to Rederij Groen on 16 March 2020 as planned.

Removal of existing cement tank
Installation of yard pre-fabricated fuel oil tanks
The Mariska G departing from Tuas Yard, ready to take on seismic operations