The Design of an Eight-Oared Rowing Shell

1993 ◽  
Vol 30 (02) ◽  
pp. 84-99
Author(s):  
Carl A. Scragg ◽  
Bruce D. Nelson
Keyword(s):  
Shallow Water ◽  
High Speed ◽  
Hull Form ◽  
Model Scale ◽  
Minimum Drag ◽  
Final Design ◽  
Minimum Displacement ◽  
Resistance Curves ◽  
Hull Forms ◽  
Minimum Resistance

Rules governing the design of rowing shells do not restrict basic hull parameters. In designing a new eight-oared rowing shell for international ard Olympic competition, the authors sought a high speed, minimum drag hull form, subject only to the constraints on minimum displacement and roll stability. An investigation of optimum hull parameters using analytically determined resistance curves was made. Optimum hull parameters for both deep and shallow water racing are presented. Using the hull parameters determined for minimum resistance at racing speeds in shallow water, several new hull forms were created and analyzed in both deep and shallow water. Two promising final design candidates were proposed for model-scale testing. Results of both steady and unsteady towing tests are presented.

ON THE MACRO HYDRODYNAMIC DESIGN OF HIGHLY EFFICIENT MEDIUM- SPEED CATAMARANS WITH MINIMUM RESISTANCE

2021 ◽  
Vol 154 (A3) ◽  
Author(s):  
M Haase ◽  
J Binns ◽  
G Thomas ◽  
N Bose ◽  
G Davidson ◽  
...  
Keyword(s):  
High Speed ◽  
Preliminary Design ◽  
Total Resistance ◽  
Hull Form ◽  
Transport Efficiency ◽  
New Class ◽  
Highly Efficient ◽  
Medium Speed ◽  
Resistance Curves ◽  
Minimum Resistance

A new class of fuel-efficient and environmentally friendly twin-hull vessels is currently under development. Compared to high-speed catamarans, a significant reduction in speed combined with an increase in deadweight tonnes will lead to a highly efficient medium-speed catamaran design. Recently-built conventional and high-speed ferries are compared to each other in terms of length, speed, deadweight and transport efficiency to classify the new design. The goal of this study is to find a preliminary macro design point for minimum total resistance by considering the main particulars of the catamaran vessel: block coefficient, prismatic coefficient and slenderness and separation ratios of the demihulls. Publications containing recommendations towards the optimum hull form parameters for moderate Froude numbers are reviewed and existing experimental data analysed to identify parameters for this new class of vessel. Designs with varied L/BOA-ratios and constant deck area are compared to find configurations of low total resistance for carrying a nominated deadweight at a particular speed, the associated change of the light ship weight has been taken into account. Two different model test series of catamaran models have been considered and their resistance curves agreed to each other. Recommendations are made; with the most important being the vessel should not exceed a speed of Fr = 0.35, with optimal prismatic coefficients around CP ≈ 0.5 and low transom immersion. This study presents the preliminary design of medium-speed single and twin-hull vessels for operations close to hump speed.

On The Macro Hydrodynamic Design Of Highly Efficient Medium-speed Catamarans With Minimum Resistance

2012 ◽  
Vol 154 (A3) ◽  
Keyword(s):  
High Speed ◽  
Preliminary Design ◽  
Total Resistance ◽  
Hull Form ◽  
Transport Efficiency ◽  
New Class ◽  
Highly Efficient ◽  
Medium Speed ◽  
Resistance Curves ◽  
Minimum Resistance

A new class of fuel-efficient and environmentally friendly twin-hull vessels is currently under development. Compared to high-speed catamarans, a significant reduction in speed combined with an increase in deadweight tonnes will lead to a highly efficient medium-speed catamaran design. Recently-built conventional and high-speed ferries are compared to each other in terms of length, speed, deadweight and transport efficiency to classify the new design. The goal of this study is to find a preliminary macro design point for minimum total resistance by considering the main particulars of the catamaran vessel: block coefficient, prismatic coefficient and slenderness and separation ratios of the demihulls. Publications containing recommendations towards the optimum hull form parameters for moderate Froude numbers are reviewed and existing experimental data analysed to identify parameters for this new class of vessel. Designs with varied L/BOA-ratios and constant deck area are compared to find configurations of low total resistance for carrying a nominated deadweight at a particular speed, the associated change of the light ship weight has been taken into account. Two different model test series of catamaran models have been considered and their resistance curves agreed to each other. Recommendations are made; with the most important being the vessel should not exceed a speed of Fr = 0.35, with optimal prismatic coefficients around CP ≈ 0.5 and low transom immersion. This study presents the preliminary design of medium-speed single and twin-hull vessels for operations close to hump speed.

scholarly journals On the Development of Catamaran Hull Form for Fish Processing Vessel to Support Domestic Fishing Activities in Indonesia

Naše more ◽  
2021 ◽  
Vol 68 (3) ◽  
pp. 175-188
Author(s):  
Ahmad Fauzan Zakki ◽  
◽  
Deddy Chrismianto ◽  
Aulia Windyandari ◽  
Rizaldy Ilham
Keyword(s):  
Dynamic Stability ◽  
High Speed ◽  
Equation Model ◽  
Fish Processing ◽  
Hull Form ◽  
Initial Stage ◽  
Intact Stability ◽  
Principal Dimension ◽  
Hull Forms ◽  
Resistance Performance

Several advantages of multihull, such as catamaran, have been extensively discussed in the previous research. Therefore, this research focuses on developing a catamaran hull form for the fish processing vessel hull. The initial stage is determining the principal dimension and exploring the configurations of catamaran hull forms. The existing high-speed craft catamarans have been adopted to determine the parent model main dimensions using a linear regression equation model. Otherwise, the catamarans single demi-hull geometry was developed by converting and modifying the parent model hull form with enlarging the hull displacement to achieve the deadweight capacity and service speed requirements. The demi-hull spacing configuration with s/L 0.17, s/L 0.20, s/L 0.30, and s/L 0.40 on the resistance characteristics, intact stability, and sea-keeping behaviour were also explored. Furthermore, the comparisons with the previously proposed monohull were presented. Regarding the hull resistance performance, the analysis indicated that the catamaran hull form had better total resistance characteristics than the monohull on the service speed over 23 knots. In the case of intact stability, the analysis results presented that the catamaran hull form has better intact stability characteristics than the monohull. The dynamic stability of the catamarans also gave better dynamic stability at the heeling angle below 41.57°. Otherwise, the catamarans with s/L 0.17 and s/L 0.20 have lower dynamic stability than the monohull at the heeling angle larger than 41.57° and 58.03°, respectively. In the sea-keeping performance, the catamaran hull has shown an excellent rolling motion required for the offshore environment loading/unloading process. The large demi hull spacing of the catamarans hull can reduce the effect of the wave creating load on the roll motion response at the Beam Sea.

scholarly journals Geometric Considerations for the Design of Production-Friendly High-Speed Ship Hull Forms

2005 ◽  
Vol 219 (2) ◽  
pp. 65-76
Author(s):  
S W Boyd ◽  
A H Day ◽  
I E Winkle
Keyword(s):  
Conceptual Design ◽  
High Speed ◽  
Three Dimensional ◽  
Construction Cost ◽  
Hydrodynamic Resistance ◽  
Material Strength ◽  
Construction Technique ◽  
Hull Form ◽  
Double Curvature ◽  
Hull Forms

This study examines the feasibility of designing high-speed ships with hull-form geometry suitable for planked construction, with the aim of reducing the hull construction cost. An algorithm is developed for placing prismatic planks on to a three-dimensional hull form to represent a planked construction. A number of well-known hull forms are examined using the algorithm developed in order to assess their suitability for this construction technique. It is shown that typical round-bilged forms are unsuitable for planked construction, since an undesirably large proportion of the material strength will be used in forming the structure. A conceptual design for a simplified hull form is developed which contains significantly reduced levels of double curvature, and this design is shown to be suitable for planked construction, as well as offering the potential for advantages in conventional plated construction. It is further shown that the hydrodynamic resistance of this conceptual design is comparable with a more traditional form.

Optimization on Resistance Performance of High Speed Unmanned Surface Vehicle in Middle-Low Speed

2011 ◽  
Vol 311-313 ◽  
pp. 2389-2392
Author(s):  
Wei Jia Ma ◽  
Hua Wei Sun ◽  
Yong Jie Pang
Keyword(s):  
High Speed ◽  
Optimization Method ◽  
Resistance Coefficient ◽  
Total Resistance ◽  
Hull Form ◽  
Unmanned Surface Vehicle ◽  
Low Speed ◽  
Non Linear Programming ◽  
Hull Forms ◽  
Resistance Performance

Unmanned surface vehicle has been the concern of the researchers at home and abroad as a new kind of unmanned platform ,especially for the middle-low speed resistance performance .An optimization method is proposed in this paper to find a hull form with perfect resistance performance in middle-low speed .This paper combines wave resistance and non-linear programming , Moreover, some hull forms are optimized to meet the combination of optimization punishing function with practical requirements and objective function to obtain Optimization form. The paper compared wave-making resistance coefficient and Total resistance (Newton) of Unit displacement (ton) between patent form and Optimization form to Show the feasibility of this method .The optimization results can provide reference for the subsequent hull form.

AL TECH 203EZ and 303EZ

Alloy Digest ◽  
1978 ◽  
Vol 27 (11) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Stainless Steels ◽  
High Speed ◽  
Heat Treating ◽  
Temperature Performance ◽  
Final Design ◽  
Mechanical Properties And Corrosion ◽  
Specialty Steel ◽  
Machining Operations ◽  
Machining Characteristics

Abstract AL Tech 203EZ and 303EZ are non-magnetic, austenitic, free-machining stainless steels specifically designed for use in high-speed, automatic machining operations. These modifications retain, in so far as possible, the good mechanical properties and corrosion resistance of the basic compositions which they represent. Sulfur or selenium is added to produce the free-machining characteristics. Data are typical; do not use for specification or final design. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-358. Producer or source: AL Tech Specialty Steel Corporation.

Development and Assessment of a Total Resistance Optimized Bow for the AE 36

1994 ◽  
Vol 31 (02) ◽  
pp. 149-160
Author(s):  
Donald C. Wyatt ◽  
Peter A. Chang
Keyword(s):  
Experimental Data ◽  
Optimization Procedure ◽  
Wave Resistance ◽  
Scale Model ◽  
Optimization Approach ◽  
Nonlinear Constraints ◽  
Total Resistance ◽  
Hull Form ◽  
Final Design ◽  
Resistance Data

A numerically optimized bow design is developed to reduce the total resistance of a 23 000 ton ammunition ship (AE 36) at a speed of 22 knots. An optimization approach using slender-ship theory for the prediction of wave resistance is developed and applied. The new optimization procedure is an improvement over previous optimization methodologies in that it allows the use of nonlinear constraints which assure that the final design remains within practical limits from construction and operational perspectives. Analytic predictions indicate that the AE 36 optimized with this procedure will achieve a 40% reduction in wave resistance and a 33% reduction in total resistance at 22 knots relative to a Kracht elliptical bulb bow design. The optimization success is assessed by the analysis of 25th scale model resistance data collected at the David Taylor Research Center deepwater towing basin. The experimental data indicate that the optimized hull form yields a 51% reduction in wave resistance and a 12% reduction in total resistance for the vessel at 22 knots relative to the Kracht bulb bow design. Similarly encouraging results are also observed when comparisons are made with data collected on two other conventionally designed AE 36 designs.

Some Guidance for Hull Form Selection for SWATH Ships

1988 ◽  
Vol 25 (04) ◽  
pp. 239-252
Author(s):  
G. Robed Lamb
Keyword(s):  
High Speed ◽  
Early Stage ◽  
The United States ◽  
Practical Application ◽  
Hull Form ◽  
Stage Design ◽  
Seakeeping Performance ◽  
The World ◽  
Selection For ◽  
Early Stage Design

Even though in 1987 there were only a dozen SWATH (smali-waterplane-area twin-hull) craft and ships afloat around the world, word of their markedly superior seakeeping performance is spreading rapidly. The number of SWATH vessels is likely to double within five years. As in many other areas of technology, the United States and Japan are the acknowledged leaders in the development and practical application of the SWATH concept. This paper reviews the characteristics of existing SWATH craft and ships from the standpoint of the stated seakeeping objective. Hull form differences between four SWATH craft and ships, including the Navy's SSP Kairnalino, are analyzed and interpreted. Important considerations for the early-stage design of a SWATH ship are discussed. Differences in the range of feasible hull form geometries for coastal areas and unrestricted ocean operations, and for low-speed versus moderately high-speed applications, are pointed out.

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