Florian Sprenger

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

Design Parameters for Increased Operability of Offshore Crane Vessels

Marine subsea operations are performed by highly specialized ships, referred to as Inspection, Maintenance, and Repair (IMR) and Offshore Construction Vessels (OCV). Although the ships and their on-board equipment are designed to operate in harsh environmental conditions, the current practice often is to terminate operations when a rigid and conservative weather limitation is reached, often specified in terms of the significant wave height as the exclusive criterion. Such general limitations do not account for vessel specific motion behavior. Since the offshore industry is aiming for all-year-round safe subsea operations, there is a strong interest amongst ship designers, owners and operators to establish vessel and task specific criteria. The project Vessel Performance within the Norwegian Centre for Research-based Innovation on Marine Operations (SFI MOVE), is developing response-based procedures, that are leading to case-specific operational ranges. This approach enables the full exploitation of vessel performance capabilities for safe and efficient offshore operations. Two methods with different complexity levels are proposed. Firstly, on the higher level, detailed operability analysis for a fleet and sea area of interest are performed by means of numerical tools. ∗Address all correspondence to this author. †Formerly MARINTEK, since January 1st 2017 SINTEF Ocean through an internal merger in the SINTEF Group This level can be used to obtain detailed results for existing ships, but the procedure can also be applied as guidance in the design stage. Secondly, on the lower level, generic diagrams can be used to estimate and compare the operational performance of different vessels based on fact sheet parameters. This is especially relevant for decision making processes where a detailed study cannot be performed. INTRODUCTION All-year-round marine operations are currently the focus of many oil companies, as a consequence of increased efforts and investments to prolong production from mature fields. This implies installation and maintenance of complex equipment also during the winter season (80% availability typically implies North Atlantic operations in significant wave heights up to 4.5 m or 5.0 m [1]) and hence high availability. Such operations require special weather insensitive handling equipment and more precise data for hydrodynamic loads on both the vessel hull and the complex module structure that is subject to strongly transient and non-linear processes when lowered through the splash zone [2]. The vessels being used in different types of marine operations have different capacities (craneand winch capacity, deck area, dead weight, etc.), equipment and safety barriers (redundancies, freeboard and protection of working Proceedings of the ASME 2017 36th International Conference on Ocean, Offshore and Arctic Engineering OMAE2017 June 25-30, 2017, Trondheim, Norway