Dariusz Fathi

Exposed Aquaculture in Norway

Farming of Atlantic salmon in exposed areas poses unique challenges to operations, structures and equipment due to severe and irregular wind, wave and current conditions, and sheer remoteness. Many of the operational challenges seen at present sheltered sites are likely to be amplified when moving production to more exposed locations. There is, however, a strong Norwegian industrial interest in utilizing such areas. A new research center, the Exposed Aquaculture Operations center has been initialized to develop competence and technology to address the challenges. Six core research areas are identified that will be crucial to address the challenges with exposed farming, with a focus on the industrial status in Norway. Four areas target technological innovations that will enable safe and reliable exposed aquaculture operations: 1) Autonomous systems and technologies for remote operations, 2) Monitoring and operational decision support, 3) Structures for exposed locations and 4) Vessel design for exposed operations. Two areas represent core requirements for sustainable production: 5) Safety and risk management and 6) Fish behavior and welfare. This paper describes the research needs and the research strategy planned for the Exposed Aquaculture Operations center.

Virtual Prototyping of Maritime Systems and Operations

While in aerospace and automotive industry, airplanes and cars are built in quantity, in maritime industry ships and offshore platforms are built uniquely such that even sister ships can be significantly different from each other. Hence, building a full scale prototype to test, verify, and demonstrate effectiveness of new innovative solutions, is not an option in maritime sector. Model testing and simulation of separate modules have been practiced in many applications successfully, however, capturing the complete interaction of different modules in a maritime system is not straight forward. To best of our knowledge, the modeling and simulation of a maritime system to the extent where the complete system, including the mutual interactions, is not accomplished yet. A maritime system incorporates a wide variety of components from different engineering fields and in order to develop a simulation framework for such a complex system, an interdisciplinary effort is needed from different branches of science including but not limited to hydrodynamics, machinery and power systems, structural engineering, navigation and control. This paper aims to introduce a joint effort from different research institutes, universities, and industrial partners to shed a light on the different issues in virtual prototyping in maritime systems and operations. It summarizes some of the available frameworks for virtual prototyping, and ends with a numerical simulation of a generic hull model coupled with propellers, propeller actuators, DP controller, thrust loss calculations, wind, waves and current, performed with the current implementation of our Virtual Prototyping Framework (VPF).© 2016 ASME

Identification of Nonlinear Manoeuvring Models for Marine Vessels Using Planar Motion Mechanism Tests

A nonlinear manoeuvring model in three degrees of freedom is presented. MARINTEK’s approach to the numerical determination of this manoeuvering model’s parameters is then shown. Finally the process of taking advanced experimental methods, and utilising MARINTEK’s numerical tools to generate an advanced model available for use in VeSim, MARINTEK’s in-house simulator tool, is shown as a demonstration that the model combined with numerical tools is of great use in making manoeuvring predictions.Copyright

Time Domain Simulation Model for Research Vessel Gunnerus

A research vessel (RV) plays an important role in many fields such as oceanography, fisheries and polar research, hydrographic surveys, and oil exploration. It also has a unique function in maritime research and developments. Full-scale sea trials that require vessels, are usually extremely expensive; however, research vessels are more available than other types of ship. This paper presents the results of a time-domain simulation model of R/V Gunnerus, the research vessel of the Norwegian University of Science and Technology (NTNU), using MARINTEK’s vessel simulator (VeSim). VeSim is a time-domain simulator which solves dynamic equations of vessel motions and takes care of seakeeping and manoeuvring problems simultaneously. In addition to a set of captive and PMM tests on a scale model of Gunnerus, full-scale sea trials are carried out in both calm and harsh weather and the proposed simulation model is validated against sea trial data.Copyright

Manoeuvring Validation Analysis of the M/F Landegode

A framework is described in which a manoeuvring simulator can be built up from model tests. It is applied to a modern LNG powered RORO ferry, the M/F Landegode, with model tests and computational results being used to make full-scale predictions. These predictions are tested against full-scale manoeuvring performance measurements, and are shown to be of a high quality.Copyright

Drifting Paths of Disabled Vessels

Many maritime emergency situations involve drifting vessels, and tools to predict drifting patterns have been developed by meteorology institutes, class societies and research companies. It is important to be able to predict a vessel’s drifting path and to estimate when it will drift into waters where grounding is a possible outcome. Such a prediction tool would provide valuable input to the planning of an emergency towing operation to prevent the vessel from grounding or to reduce the impact of the grounding.In this paper we present the outcomes of a study that investigated the drifting pattern of a vessel with an engine shut-down in the Barents Sea. As part of the ongoing A-Lex project [1], MARINTEK has prepared a VeSim [2] model to investigate the drifting path of a cargo vessel. The outcomes of the study will be used to draw up a technical specification for work to be done to develop an improved ship drift model in Norwegian Meteorological Institute’s (MET Norway’s, [3]) new Halo platform [4]. An improved model will be of great help to those planning emergency towing operations and for positioning of emergency preparedness units with respect to the traffic situation (especially tracks of vessels carrying dangerous goods) and weather forecasts.© 2015 ASME

Experimental results on motion regulation in high speed marine vessels

A design procedure of an active ride control system (RCS) for regulating the roll and pitch motions of a high speed marine vessel is presented. In order to achieve high quality passenger comfort and reduce the seasickness it is necessary to counterbalance the excessive pitch and roll motions using an active ride control system. To do so, a mathematical model of the vessel describing the motion of the high speed vessel in 3 degree of freedom, heave-roll-pitch, is derived using VERES (VEssel RESponse) program. The effect of active T-foils and interceptors is discussed, and a frequency weighted H2-optimal controller is designed and implemented. The performance of the proposed ride control system is shown by experimental tests of a scaled model of high speed catamaran in MARINTEKs ocean basin.