The most technologically advanced marine diamond sampling and exploration vessel in the world – the Debmarine-owned mv SS Nujoma pictured in Cape Town’s harbour. Hytec was responsible for all hydraulics pertaining to the vessel’s heave compensation system, launch and recovery system and the world-first advanced sub-sea sampling system called Seabed Tool.
In its biggest sea vessel project ever undertaken, Hytec successfully designed, manufactured, installed and commissioned all hydraulics for three systems on board the most technologically advanced marine diamond sampling and exploration vessel in the world for its client De Beers Marine. Hytec, part of the Hytec Group, was responsible for all hydraulic related aspects of the heave compensation system, the launch and recovery system (LARS) and a world-first advanced sub-sea sampling system called Seabed Tool (SBT) for the brand new Debmarine Namibia-owned sampling vessel, the mv SS Nujoma.
Contracted by De Beers Marine South Africa in Cape Town, Hytec Cape Town was brought into the project as far back as 2012 for the pre-feasibility and feasibility studies. These were completed during the first half of 2015 and Hytec received the hydraulic orders for the SBT in July 2015 and for the LARS in September the same year. Design, manufacture, assembly and successful testing of the SBT were completed in July 2016, while the manufacture and assembly of the LARS system modules, carried out in Johannesburg, was completed and delivered to De Beers Marine in Cape Town, in August 2016.
Scope of work
Hytec’s scope of work included the hydraulic installation and testing of the heave compensation system and the design, manufacture and installation of the LARS and the SBT hydraulic systems. The LARS and the SBT hydraulic systems were both designed and manufactured by Hytec and the passive heave compensation system was designed and manufactured by Bosch Rexroth in Boxtel, Netherlands. All systems were designed using high quality Bosch Rexroth equipment. The passive heave compensation system comprises cylinders connected to a hydraulic power unit and accumulator banks.
The hydraulic ring main for the LARS comprised a central hydraulic power pack. The power pack supplies oil through the ring main to the equipment used to launch and recover the SBT and consists of multiple winches and handling systems.
The SBT hydraulic system has power units with a combination of Bosch Rexroth open and closed loop pumps to power the subsea mining equipment. “The hydraulic system is designed for subsea use of up to 200 m,” explains Herman van Rensburg, Regional Technical Manager, Hytec Cape Town.
A view from the deck of the Seabed Tool (SBT), a world-first advanced sub-sea sampling system aboard the mv SS Nujoma. The SBT hydraulic system has power units with a combination of Bosch Rexroth open and closed loop pumps to power the subsea mining equipment.
Installation, commissioning and hand-over
The vessel arrived in Cape Town harbour in mid-August 2016, where De Beers Marine commenced the installation of the Mission Equipment, into the vessel. The Mission Equipment included the sampling system, and a high tech batching diamond treatment plant constructed in modules on the quay for rapid installation onto the vessel. The sampling system on-board pipe installation was conducted during September and October 2016 with Hytec staff working 12 hours a day, 7 days a week. In-harbour commissioning began at the end of October with maiden sea trials conducted just outside of Cape Town in November 2016. Subsequent to a short in-port stay, the mv SS Nujoma began additional sea trials and final commissioning on the West coast of South Africa during December 2016. The vessel was delivered to Debmarine Namibia in March 2017 and is currently in full sampling operation.
The sampling system modules, with the heaviest weighing more than 220 tonnes, were lifted onto the vessel using the second largest super-lift crane in southern Africa.
The ship was constructed by Kleven Verft Shipbuilding Company in Norway, and named after Namibia’s founding president, Dr Sam Shafiishuna Nujoma. However, all the mission equipment was built in South Africa. The majority of the equipment for the hydraulic systems was imported from Bosch Rexroth in Germany in component format, with most of the modules built in Hytec Johannesburg’s facility. “In fact,” points out van Rensburg, “we stretched our manpower by utilising Hytec resources from around the country in order to put this system together. This is indicative of Hytec’s internal collaboration to ensure we provide not only optimum machinery and equipment to our clients, but optimum service too.”
The US$157 million mining exploration vessel is 113 m long, 22 m wide with a displacement of 12 000 tonnes. It accommodates a crew of 80 and will carry out sampling for a three-year exploration operation before returning to port for maintenance.
Hytec Cape Town has been providing hydraulic services to DeBeers Marine for over 30 years, and the last time a project of this magnitude was undertaken was in 2006 when DeBeers Marine converted a second-hand vessel to a crawler mining vessel.
Hytec is a subsidiary of the Hytec Group - an official Bosch Rexroth company.
A front view of the launch and recovery system (LARS) and SBT during installation. The hydraulic ring main for the LARS comprised a central hydraulic power pack, which supplies oil through the ring main to the equipment used to launch and recover the SBT.