Hans Hopman

Challenges in computer applications for ship and floating structure design and analysis

This paper presents a review on the key research areas in the design and analysis of ships and floating structures. The major areas of computer application are identified in several stages of ship/floating structure design and analysis with the principal emphasis on the methodologies, the modeling, and the integration of the design and analysis process. The discussion addresses some of the key challenges in computer applications for ship and floating structure design and analysis, and reports on the emerging trends in the research, design and industrial application.

Combining a Knowledge System with Computer-Aided Design

Abstract The knowledge-based shell Quaestor is linked to the NURBS modeller Rhinoceros. The resulting CAD system enables the efficient integration of various types of design knowledge, creating a flexible and integrated design model. Several applications in the field of ship design show the potential of the approach.

A quantitative comparison of hybrid diesel-electric and gas-turbine-electric propulsion for future frigates

Future frigates need to reduce fuel consumption and emissions, while improving effectiveness. This paper quantitatively compares top speed, fuel consumption, emissions, acceleration performance and engine loading of hybrid diesel-electric and gas-turbine-electric propulsion, using validated models and introducing sequential turbocharging and power take-off. This simulation study demonstrates hybrid diesel-electric propulsion can reduce fuel consumption and CO2 emissions by 10% to 25% compared to gas-turbine-electric propulsion, while reducing top speed by 3 kts. Moreover, hybrid diesel-electric propulsion is found to provide good acceleration without thermally overloading the engine when speed control is employed for the electric drive in combination with torque control for the diesel engine.

New Estimation Methods for the Steel Weight of European Inland Dry Bulk Ships

There are hardly any methods available for the estimation of the steel weight of inland ships in the earliest design stages. The few weight estimation methods that are available are out of date, limited to a narrow band of main dimensions and not sensitive enough to be used for innovative designs. In this article, which summarizes key results from the PhD thesis of Hekkenberg (2013), new methods are derived for the estimation of the steel weight of inland dry bulk ships. The estimation methods that are presented are derived from large systematic series of computer-generated ship designs that comply with Lloyds Registers rules regarding their structure and with the European rules for freeboard. The structure and weight of these designs are validated by a comparison of modeled scantlings with the scantlings of midship sections of existing ships. Further validation is done by a comparison of the modeled overall steel weight with the steel weight of actual ships and the weight estimates of existing methods. The designs are used to derive two types of estimation methods: the first is a set of simple formulas that are valid for inland ships with common sizes and L/B ratios and the second is a more complex set of formulas that allows estimation of the steel weight of inland ships with draughts ranging from 1.5 to 4.5 m, lengths of 40‐185 m, beams of 5‐25 m, and L/B ratios of 4‐20.

An Optimisation-Based Space Allocation Routine for the Generation of Feasible Ship Designs

Abstract A proof-of-concept of an optimisation-based space allocation approach for the conceptual design of ships is presented. A space allocation routine, integrated with a genetic algorithm, generates a large and diverse set of feasible concept designs, from which the designer can select the designs best reflecting the current set of priorities, without creating designs that cannot exist, e.g. by being insufficiently stable. As a result, the human designer is provided with flexibility at a high level of detail and can therefore focus on resolving difficult compromise decisions. A test case dealing with the design of an offshore patrol vessel shows the possibilities of the new approach.

Strategic guidance based on the concept of cleaner production to improve the ship recycling industry

The implementation of international ship recycling regulations and international standards of health, safety and environment on a ship recycling yard improves environmental protection, occupational health and safety of the workers. However, it results in increased costs of the ship recycling process, which is detrimental for offering a high price to ship owners for buying end-of-life ships. In order to improve their competitiveness in the market, such “green” recycling yards, as they are generally called, must either increase the revenue or reduce the costs of the ship recycling process. Apart from this, being regulatory compliant, such yards must also plan the recycling process systematically. This paper aims to identify strategies that can help recycling yards achieve these objectives. The effective strategies are identified using the concept of cleaner production. It is chosen because it is a preventive environmental strategy that provides generic options to improve the financial and environmental performance of the production firms. The applied research method first establishes that the ship recycling process can be considered as a production process and then reviews each of the generic cleaner production options with respect to ship recycling. As a result, three strategies are identified, which are material flow analysis, design-for-recycling and waste-to-energy technology.

Definition of Ship Outfitting Scheduling as a Resource Availability Cost Problem and Development of a Heuristic Solution Technique

The outfitting process of shipyards building complex ship types, such as offshore, passenger, and military vessels, is becoming more critical to efficient ship production as the number of components installed on these vessels continues to increase. Outfitting of such vessels is generally characterized by disorganization and rework due to a lack of coordination between the shipyard and subcontractors as well as insufficiently detailed planning. This paper presents a mathematical model for the outfitting planning process of a shipyard building complex vessels. A qualitative description is included for the constraints and objectives underlying the developed mathematical model for the Ship Outfitting Scheduling Problem (SOSP). A heuristic solution technique is also developed for solving the SOSP, and a test case of six midship sections from a recently constructed pipelaying vessel is presented to show the feasibility of both the mathematical model and heuristic. This test case shows that it is possible to find a high-quality planning for the SOSP with a reasonable computational effort. Furthermore, it was found that the greatest priority should be given to components that have the earliest deadlines or dependents with such deadlines. Components should also be scheduled in such a way to minimize the required movements of outfitting personnel between the different work sites of a shipyard.