Evaluation of propeller-hull interaction in early stage of ship design

2010 ◽  
pp. 261-268
Author(s):  
R Grubi_i_
Keyword(s):  
Early Stage ◽  
Ship Design

The Quadrimaran Reexamined

2015 ◽  
Author(s):  
William A. Hockberger
Keyword(s):  
High Performance ◽  
Early Stage ◽  
Ship Design ◽  
Technical Problems ◽  
Additional Information ◽  
Marine Vehicles ◽  
Detail Design ◽  
Marine Industry ◽  
And Performance ◽  
Met Expectations

The Quadrimaran was invented in France in the mid-1980s by Daniel Tollet. It was an inspired design and a radical departure from traditional ship design by a man from outside the marine industry unconstrained by industry technical practices and education. Technical experts could see it would entail more structure and subsystems than other high-performance vessels, but its promise was that those penalties would be more than offset by its claimed low power and fuel consumption. A prototype/demonstrator, Alexander, was built in 1990 and operated for five years carrying and impressing many hundreds of riders. Alexander performed beautifully and appeared to bear out what was claimed. Contracts for several Quadrimarans of different sizes came quickly, especially considering how conservative an industry this is. That was significantly due to Tollet's personal charisma and skill in selling riders on the dream of carrying passengers and freight over the water fast and in comfort, yet economically. Great skepticism prevailed in some quarters, especially among naval architects knowledgeable about AMVs (advanced marine vehicles) and early-stage whole-ship design. At technical meetings, one Quadrimaran principal would comment, for example, "Why would you carry freight across the Atlantic at 38 knots on 230,000 horsepower (a reference to the planned Fastship Atlantic TG-770) when you could do it at 60 knots on only 65,000 horsepower?" Listeners would ask how this could be possible, and he would assert again that the Quadrimaran could do it, but would decline to explain. Respected technical people were working with Tollet and his company and becoming convinced of the Quadrimaran's merit. Along with the contracts came engineers with experience in ship detail design and construction (very different from early-stage whole-ship design), or responsibilities for assessing and approving ships for service. Others were with engine and equipment suppliers. Their opinion that there was something unique and special about the Quadrimaran gave it credibility and influenced more people to accept the major claims made for it. Some dismissed the most extreme claims but still accepted the idea that the Quadrimaran was capable of unusually high performance - considerably less than was being claimed, perhaps, but high nevertheless. In hindsight it is clear the skeptics were right. Results never met expectations, nor could they have. In reality, the Quadrimaran has aspects that inherently prevent it from achieving the characteristics and performance its inventor believed attainable. It cannot be built in a commercially useful size and actually perform as intended. Why this is so will be explained. A crucial fact in the Quadrimaran's history is that Daniel Tollet and his close associates believed strongly that naval architects and engineers who had been immersed in working with the existing ship types would be unable to give the Quadrimaran the very different treatment they believed it required. (Their own educations and professional work were nontechnical.) Such people were excluded from the development of Quadrimaran designs, and the belated discovery of many fundamental technical problems can be attributed to this. The company Tollet established had a number of names over the years, and other associated entities were created at times for various purposes. In this paper they are referred to collectively as QIH (Quadrimaran International Holdings) so as not to confuse things unnecessarily. In 2004 QuadTech Marine LLC was established and acquired the Quadrimaran patent (US Patent No. 5,191,849) and related intellectual property from QIH. QuadTech laid out an extensive R&D program to close gaps in the technical background and address identified issues. In the process, additional information on earlier QIH projects and products was obtained and studied, which brought to light problems that significantly compromised the Quadrimaran's prospective performance and utility. The resulting much-reduced set of potential uses and users led the company to effectively stop pursuing Quadrimaran projects after 2009. (Note: The author was Chief Technology Officer for QuadTech Marine during 2006-9, studying the Quadrimaran and planning the R&D.)

scholarly journals A Study into the Validity of the Ship Design Spiral in Early Stage Ship Design

2017 ◽  
Vol 33 (02) ◽  
pp. 81-100
Author(s):  
Rachel Pawling ◽  
Victoria Percival ◽  
David Andrews
Keyword(s):  
Design Process ◽  
Early Stage ◽  
Ship Design ◽  
Complex Process ◽  
University College London ◽  
The University ◽  
Convenient Model ◽  
Balanced Solution ◽  
Block Approach ◽  
Design Spiral

For many years, the design spiral has been seen to be a convenient model of an acknowledged complex process. It has virtues particularly in recognizing the ship design interactive and, hopefully, converging nature of the process. However, many find it unsatisfactory. One early criticism focused on its apparent assumption of a relatively smooth process to a balanced solution implied by most ship concept algorithms. The paper draws on a postgraduate design investigation using the University College London Design Building Block approach, which looked specifically at a nascent naval combatant design and the issues of size associated with "passing decks" and margins. Results from the study are seen to suggest that there are distinct regions of cliffs and plateau in plots of capability against design output, namely ship size and cost. These findings are discussed with regard to the insight they provide into the nature of such ship designs and different ways of representing the ship design process. The paper concludes that the ship design spiral is a misleading and unreliable representation of complex ship design at both the strategic and detailed iterative levels.

Characterizing general arrangements and distributed system configurations in early-stage ship design

2018 ◽  
Vol 163 ◽  
pp. 107-114 ◽  
Author(s):  
Colin P.F. Shields ◽  
Michael J. Sypniewski ◽  
David J. Singer
Keyword(s):  
Distributed System ◽  
Early Stage ◽  
Ship Design ◽  
System Configurations

scholarly journals The Lightship Mass Calculation Model Of A Merchant Ship By Empirical Methods

2021 ◽  
Vol 93 (6s) ◽  
pp. 73-87
Author(s):  
Vedran Slapničar ◽  
◽  
Katarina Zadro ◽  
Viktor Ložar ◽  
Ivo Ćatipović ◽  
...  
Keyword(s):  
Least Squares Method ◽  
Early Stage ◽  
Calculation Model ◽  
Ship Design ◽  
Empirical Methods ◽  
Construction Costs ◽  
Hull Steel ◽  
The One ◽  
The Masses ◽  
Preliminary Phase

Estimating the lightship mass is an important factor in the early stage of ship design given its impact on shipbuilding costs. The mass of the hull and equipment, as well as its distribution, affects the hull strength, deadweight, and stability of the ship. Furthermore, a good estimate of the lightship mass in the preliminary phase is very important for defining the construction costs as accurately as possible. As the time available to the designer in the conceptual or preliminary phase of ship design is often limited, the methods used to determine the lightship mass must be reliable, fast, and effective. The paper presents and analyzes methods for estimating the lightship mass that are based on empirical data of built ships. Several empirical methods were combined and calibrated to establish the least-squares method which combination gives the value of the lightship mass closest to the one given in the collected database for three types of merchant ships: tankers, bulk carriers, and container ships. The paper presents the results of the calculations of the masses of hull steel, outfitting, machinery, and superstructure. It can be concluded that the presented model for all three types of merchant ships gives satisfactory results.

Hull Form Optimization for Early Stage Ship Design

2010 ◽  
Vol 122 (2) ◽  
pp. 53-65 ◽  
Author(s):  
WESLEY WILSON ◽  
DANE HENDRIX ◽  
JOSEPH GORSKI
Keyword(s):  
Early Stage ◽  
Ship Design ◽  
Hull Form

Overwelding and distortion control for naval surface combatants

2012 ◽  
Author(s):  
T. D. Huang ◽  
M. Harbison ◽  
L. Kvidahl ◽  
D. Niolet ◽  
J. Walks ◽  
...  
Keyword(s):  
Thin Plate ◽  
Early Stage ◽  
Steel Structures ◽  
Ship Design ◽  
Rate Of Change ◽  
Fillet Welds ◽  
Naval Research ◽  
Process Technology ◽  
Thin Steel ◽  
Dimensional Management

As high-strength thin-steel usage in ship design increases, dimensional management becomes very critical to control rework costs and schedule delays in ship production. Prior Office of Naval Research (ONR) and National Shipbuilding Research Program (NSRP) projects have helped Ingalls Shipbuilding to emphasize dimensional control for thin steel structures. Huntington-Ingalls (previous Northrop Grumman Shipbuilding) has, in recent years, substantially increased its emphasis on dimensional management as an enabler to achieving its aggressive goals for the future. These goals include cost and lead time reduction for hull erection and increasing early-stage outfitting. Nevertheless, improvements to shipbuilding facilities and process technology have not kept pace with the rate of change in ship design. Worse, new designs using thinner steels are subject to legacy weld size requirements. These two factors result in widespread overwelding. Severe plate buckling in naval vessels has been attributed to oversized welds in thin plate ship structures. The problem of overwelding has two distinct sources: - The weld sizing method developed in the 1980s is still used in most shipbuilding specifications regardless of ship class. This prevents the incentive of application of latest technologies that can make strong, precision fillet welds for modern lightweight thin steel naval surface combatants. - Shipyard welders tend to make welds even larger than design requirement in order to satisfy Quality Assurance (QA) inspection. In a number of investigations, fillet welds requiring a leg size of 5mm are typically found to have an average size of 8mm, resulting in more than double the heat input and distortion. The approach to the solution of this overwelding problem will be described in detail in this paper: - Develop appropriate weld sizing criteria for thin plate structures-this can be facilitated by numerical modeling to ensure adequate static shear, tensile, bending, fatigue and dynamic impact capacity of structural welds; - Perform a robust designed experiment to confirm the models and establish confidence that precision weld sizes can provide necessary performance and strength throughout the design service life of the vessel.

INTRODUCING OPERATIONAL INFORMATION INTO EARLY STAGE SHIP DESIGN USING QUEUEING NETWORKS

2021 ◽  
Vol 162 (A2) ◽  
Author(s):  
K Droste ◽  
J J Hopman ◽  
A A Kana ◽  
B J Van Oers
Keyword(s):  
Queueing Networks ◽  
Strong Influence ◽  
Early Stage ◽  
Ship Design ◽  
Operational Effectiveness ◽  
Design Alternatives ◽  
Operational Information ◽  
Design Requirements ◽  
Operational Processes ◽  
Naval Architect

During the early stages of ship design a set of requirements needs to be identified, accounting for financial and technical feasibility, and operational effectiveness. This process of requirements elucidation creates a need for information regarding various design alternatives and their effect on the feasibility and effectiveness of the design requirements. When one considers internal layout and process driven ships, ships where the arrangement of spaces has a strong influence on the effectiveness of the ship's operational processes, a gap in available methods has been identified. This paper proposes a method based on queueing networks that allows a naval architect to study the effects of different arrangements on the execution of various sets of operational processes. Using this model a better understanding of the interaction between the ship's arrangement and its operational processes can be obtained. This understanding can improve the requirements elucidation process and can lead to the development of better design requirements.

Reducing Detail Design and Construction Work Content by Cost-Effective Decisions in Early Stage Naval Ship Design

2014 ◽  
Author(s):  
Robert G. Keane ◽  
Laury Deschamps ◽  
Steve Maguire
Keyword(s):  
Early Stage ◽  
Cost Effective ◽  
Ship Design ◽  
Defense Acquisition ◽  
Design Decisions ◽  
Stage Design ◽  
Work Content ◽  
Detail Design ◽  
Naval Ship ◽  
Early Stage Design

The Office of the Under Secretary of Defense, Acquisition, Technology and Logistics (AT&L) recently presented analyses of cost and schedule growth on Major Defense Acquisition Programs (MDAPs)over the last 20 years (2013, 2014). For naval ships, AT&L (2013) concluded that contract work content growth (not capability growth) dominates total cost growth statistically. In addition, costs-over-target are significant and reflect poor cost estimation or faulty framing assumptions. AT&L (2014) also concluded prices on fixed-price contracts are only “fixed” if the contractual work content remains fixed, but this is often not the case. The authors show that under-sizing the ship during concept design studies increases ship outfit density and adds complexities to the design. These early stage design decisions on sizing the ship are a major contributor to unnecessary work content growth later in Detail Design and Construction (DD&C) that cannot be eliminated no matter how productive the shipbuilder. However, new ship design methods are being developed and integrated with legacy physics-based design and analysis tools into a Rapid Ship Design Environment (RSDE)that will enable a more rational process for initially sizing ships. The authors also identify the need for early stage design measures of complexity and ship costing tools that are more sensitive to these measures, and proposed solutions that will aid decision-makers in reducing DD&C work content by making cost-effective design decisions in early stage naval ship design.

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