New dynamic positioning applications for workboats are good news for thruster manufacturers, the technology of which is increasing efficiencies and runtimes
Rising interest in dynamic positioning (DP) for workboats and for vessels being built to support offshore windfarm construction and maintenance could potentially offset a shortage of new OSV newbuilding projects and benefit thruster manufacturers.
Operators of smaller vessels require DP for positioning during offshore oil, gas and renewables and marine construction projects. DP systems of class notation DP0, DP1 or DP2 have been installed on windfarm support vessels, workboats, such as multicast and Shoalbusters, and even on coastal and port tugs.
With this market in mind, Vetus Maxwell has expanded its range of BowPro thrusters to cater for commercial workboats, using its experience from the leisure vessel sector.
Vetus Maxwell senior sales manager Pieter Feenstra says: “We would like to step into the dynamic systems market and are open to any projects. Our BowPro thrusters can be used with a much longer runtime and have a good energy efficiency.”
Vetus Maxwell cites its experience in the leisure vessel sector as evidence of the benefits it can offer to OSVs. “This is a solution and replacement for hydraulic thrusters,” says Mr Feenstra, “Because they are CANbus and proportionally controlled.”
He believes the current range is suitable for control, manoeuvring and positioning for pilot boats, search and recovery vessels, law enforcement boats and crew transfer vessels.
Vetus Maxwell’s largest thrusters were introduced to the commercial workboat market in November 2019. Bow B180 and Bow B210 are boosted thrusters with the added benefit of a third connection on the motor that permits charging of the 24 V battery bank from a 12 V or 24 V charging source, such as the propulsion engine alternator.
Its boosted models enable the thruster battery bank to be charged any time the thruster is not being used, for example if outboard motors are running, says Mr Feenstra. He says new developments will increase the durability and capabilities of these thrusters further.
“We are designing, for the bigger BowPro thrusters, a tailpiece that can stand almost unlimited runtime,” he says. “We are going to test this tailpiece in our testing facility in 2020.”
Vetus Maxwell’s thrusters can be fitted in tunnels of diameters 125 mm to 400 mm and can be converted into SternPro thrusters. Motors and electric components are fitted internally to the transom of the vessel, while the tunnel and propeller are installed externally on the transom.
The thrusters have a single lightweight and corrosion-resistant synthetic propeller for a homogeneous flow in the thruster tunnel. They also have flexible couplings between the tailpiece and motor for reduced vibrations.
They can be connected to a combined bow and stern thruster panel for manoeuvring and vessel docking. This has a joystick that when pushed towards a desired direction operates all thrusters together. The multi-axial joystick can be twisted to rotate the vessel and has a lock and hold function. It can operate thrusters either individually or simultaneously.
Elsewhere, a Chinese thruster manufacturer has teamed up with a UK-headquartered DP control provider to offer a complete system. Dutch Thrusterleader will be working with Reygar to offer DP to different class requirements for offshore support, windfarm support and marine construction vessels.
Reygar managing director Chris Huxley-Reynard thinks this is a growing trend in the sector. “We are looking to supply our DP0 control system for thruster manufacturers for positioning vessels for renewables,” he says “We are also speaking with a Chinese thruster manufacture that wants to acquire our joystick controls and part of our DP controls.”
Reygar provides remote monitoring and management software to crew transfer vessels in Europe and is expanding into Asia and North America as energy companies plan to install new offshore windfarms. It supplies BareFleet monitoring systems to CWind, Seacat Services, World Marine Offshore, Maritime Craft Services, Turner Iceni and High Speed Transfers.
Mr Huxley-Reynard believes DP systems could be installed on crew transfer vessels for positioning them close to offshore turbine foundations and towers during maintenance operations.
These could be linked with monitoring systems, such as BareFleet, to control position and prevent high forces during the interface between vessels and turbine foundations.
Integrated DP and piloting
ABB has integrated DP2 capabilities into its marine pilot control system, improving redundancy and energy efficiency for offshore support operations. It has added this functionality to ABB Ability Marine Pilot Control for offshore energy and renewables support vessels.
A joystick is used for positioning and berthing operations, including interfacing with offshore installations and turbine towers.
ABB Ability Marine Pilot Control can predict position of vessels 5-30 seconds ahead. Software then calculates the optimum method of executing motions across the operational profile of the vessel. This depends on how the operator has prioritised speed, manoeuvrability or other parameters.
Integrating DP2 functionality adds redundancy in design and operations, ensuring a vessel’s position will be maintained in the event of a single system fault.
This was demonstrated in 2019, enabling Lloyd’s Register to extend the Approval in Principle (AiP) certification it already provided for ABB Ability Marine Pilot Control to include the precision DP2 functionality.
Its AiP also confirms ABB Ability Marine Pilot Control’s DP optimises energy consumption during vessel positioning, improving the efficiency of the onboard power plant. The system accurately forecasts changes in load on the power plant, preventing peaks and managing diesel generator usage. This could have a positive impact on vessel safety, efficiency and sustainability.
Seaway 7 breaks ground with monopile installation
Seaway 7 construction vessel Seaway Strashnov has successfully installed and removed a 6.5-m diameter, 600-tonne monopile whilst in DP mode. It remained within inclination tolerances using a motion-compensated gripper.
This confirmed the feasibility of installing monopiles in DP mode, allowing the process to be repeated on the Hollandse Kust 1 & 2 and 3 & 4 offshore windfarms.
Installing large monopiles from a floating vessel in DP mode is challenging due to residual vessel motion and DP mode inaccuracies, which is why foundation installation is conducted using jack-up vessels instead.
Conference places DP technology under the spotlight
Technology for delivering power, control and position referencing to DP systems will be presented and discussed at Riviera Maritime Media’s European Dynamic Positioning Conference, in London, on 4 February 2020.
DNV GL segment director for special ships Arnstein Eknes will provide an overview of the trends and drivers in DP and technology developments.
Kongsberg Maritime DP product advisor Harry Verhoeven will consider the future for DP, its evolution, new automation and sensor technology and the use of artificial intelligence.
There will be presentations on new hybrid power and battery technology for DP systems and developments in control systems. Guidance Marine technology group manager David McKnight will present the latest innovations in laser sensors and review recent sea trials.
For more information, please visit: www.rivieramm.com/events/european-dynamic-positioning-conference