Cost-effectivity of logistical strategies for the installation of offshore wind turbine substructures

The ever-increasing size of offshore wind turbine substructures and the development of wind farms at sites further offshore, with greater water depths and with extremer weather conditions, raise logistical challenges that have never been faced before. Additionally, the offshore wind industry has to deal with governments cutting subsidies, small...

A workability study on floating installation of monopiles using the MUST

Adapting the size of upending cradles according to the ever-increasing dimensions of offshore wind turbine monopiles is costly and requires structural modifications to the associated Heavy Lift Vessels (HLVs). This study therefore investigates the potential of the Monopile Upending Smart Tool (MUST), which is a platform suspended in the HLV...

Application of greenhouse gas emission reduction technologies on a redesign of a multi-purpose heavy lift vessel

This thesis describes the process of selecting different greenhouse gas emission reduction technologies for the application on a redesign of a multi-purpose heavy-lift vessel. Only technologies were considered which did not negatively influence the operability or arrangement of the redesign. The best performing combination of technologies was...

Smart offshore heavy lift operations

Autonomous vessels have developed into a popular research area in both industry and academia. The application of autonomy in offshore and coastal engineering could offer a safe and efficient solution to offshore transportation and operation. However, the state of the art in research has focused on waterborne transportation. Very limited research...

Application of the tunnel stern to a heavy lift vessel: A design and research study using computational fluid dynamics

A variation study is conducted in which the tunnel width and depth are varied to envisage the effect on the required propulsion power and the longitudinal position of buoyancy. The propulsion power is calculated using a combined RANS - BEM model. Furthermore, the propeller is evaluated using different design difficulty indices.

Floating Installation of Windturbine Towers: A Conceptual Design Study

The demand for renewable energy is growing, due to a growing awareness among people about the effect of burning fossil fuels on the environment. Governments have signed climate agreements and are obliged to decrease their level of exhaust gasses. This change in attitude regarding the environment led to an upcoming market for renewables. A...

Observer-based robust control for dynamic positioning of large-scale heavy lift vessels

With the growing demand of large-scale heavy lift vessels in the deep-sea offshore construction works, high performance of Dynamic positioning (DP) systems is becoming ever crucial. However, current DP systems on board of heavy lift vessels do not consider model uncertainty (typically arising from mooring forces). In this paper, an observer...

Implications of a fibre rope constant tension winch for use on Pioneering Spirit's Jacket Lift System

Allseas’ Jacket Lift System (JLS) is a system which is currently being developed and capable of transporting, installing and removing a jacket of a production platform as a whole. As the Block Handling System (BHS), responsible of maintaining tension in the main hoist wires by providing a constant tension (CT) counter force, is preferably...

Large Floating Monopiles: Installation in Heavy Weather Conditions

The offshore wind market experiences large growth over the last decade. There is a clear trend to installation in deeper waters and to larger wind turbines, to maximize the energy output. The majority of offshore windmills use a monopile foundation, which due to the current trends are getting larger. Seaway Heavy Lifting (SHL) is a company that...

Monohull versus Semi-submersible for offshore heavy lift crane operations

In this thesis the differences between the monohull and semi-submersible are investigated. For a general heavy lift crane operation and its operational profile, the difference is performance and total cost are calculated. These are used to determine the turning point, the point where the semi-submersible is more favourable for a heavy lift crane...

Deterministic vessel motion prediction based on a wave radar forecast

A new development aiming to improve the safety and/or operability of offshore operations is deterministic motion forecasting. Various parties target at developing a radar which is able to detect wave trains. This deterministic wave forecast can be used to forecast vessel motions up to several minutes ahead. With such a forecast a quiescent...

Evaluation of transient lift loads during a decommissioning operation with a crane vessel

With the conversion of a heavy transport vessel into a crane vessel, Boskalis aims to strengthen its position in the offshore wind and decommissioning markets. The BOKALIFT 1, as the crane vessel will be named, is equipped with a 3,000 tonne crane and a class-2 Dynamic Positioning system. In order to utilise its exceptional large and strong deck...

Decommissioning platforms on the North Sea:: Guidelines on heavy lift vessel selection

This thesis contains the model development of a simulation model, to aid the selection of a heavy lift vessel for a North Sea decommissioning project. The model considers fixed steel platforms with maximum topside weight of 1.400 [tons].

Feasibility study on sail-equipped heavy-lift vessels