Geometric Considerations for the Design of Production-Friendly High-Speed Ship 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.

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

Naše more ◽

10.17818/nm/2021/3.5 ◽

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.

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The Design of an Eight-Oared Rowing Shell

Marine Technology and SNAME News ◽

10.5957/mt1.1993.30.2.84 ◽

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.

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Seakeeping Analysis of a High-Speed Monohull With a Motion-Control Bow Hydrofoil

Journal of Ship Research ◽

10.5957/jsr.2004.48.2.77 ◽

2004 ◽

Vol 48 (02) ◽

pp. 77-117 ◽

Cited By ~ 1

Author(s):

Paul D. Sclavounos ◽

Henning Borgen

Keyword(s):

Motion Control ◽

High Speed ◽

Three Dimensional ◽

Control Device ◽

Control Mechanisms ◽

Hull Form ◽

Active Motion ◽

Seakeeping Performance ◽

Seakeeping Analysis ◽

Longitudinal Position

The seakeeping performance is studied of a foil-assisted high-speed monohull vessel using a state-of-the-art three-dimensional Rankine panel method. The vessel is equipped with a bow hydrofoil acting as a passive heave and pitch motion-control device in waves. The formulation of the seakeeping of ships equipped with lifting appendages is developed, and the mechanisms responsible for the reduction of the heave and pitch motions of high- speed vessels equipped with hydrofoils are studied. The sensitivity of the heave and pitch motions on the longitudinal position of the hydrofoil is studied. It is found that the most efficient location for the hydrofoil is at the ship bow leading to a 50% reduction of the root mean square values of the heave and pitch motions in a Joint North Sea Wave Project (JONSWAP) spectrum. Several extensions of the analysis of the present paper are discussed. They include the reduction of the roll motion of high-speed vessels, the design of optimal active motion-control mechanisms, and the coupling of the hull form and lifting appendage design for high-speed monohull vessels.

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Experimental and Numerical Investigation of Stepped Planing Hulls in Finding an Optimized Step Location and Analysis of Its Porpoising Phenomenon

Mathematical Problems in Engineering ◽

10.1155/2020/3580491 ◽

2020 ◽

Vol 2020 ◽

pp. 1-18

Author(s):

Sayyed Mahdi Sajedi ◽

Parviz Ghadimi

Keyword(s):

Experimental Data ◽

High Speed ◽

Three Dimensional ◽

Single Step ◽

Hydrodynamic Resistance ◽

Resistance Reduction ◽

Step Model ◽

Volume Method ◽

Mesh Technique ◽

Good Agreement

Stability of a high-speed craft is an essential matter, and porpoising is one of the most critical instabilities that could occur in some planing hulls due to inappropriate design. In this paper, the porpoising phenomenon and variation of step location yielding resistance reduction are studied through experimental and numerical methods. The investigated models include a single-step model and a nonstep model with the same general shape, but with different step location. The nonstep model is previously tested, but the single-step model is examined in the present study. The nonstep model experiences porpoising at 8 m/s speed, but the single-step model remains stable at the same speed. A three-dimensional CFD analysis is conducted using the finite volume method (FVM). On the contrary, the volume of fluid (VOF) scheme is used for free surface modeling, and the overset mesh technique is implemented within StarCCM+ software. The CFD results of total hydrodynamic resistance and dynamic trim angle are compared against the experimental data. The numerical results are in good agreement with the experimental data. Subsequently, ten different stepped models are simulated to examine their effects. The longitudinal distance between steps and aft of these models are in the range of 19 to 50 percent of the length of models. The obtained results show that as steps are located farther than aft, the models become more stable, and resistance increases due to trim reduction. Finally, the optimum location of the step is extracted with the aim of minimizing the resistance through the design of experiment (DOE) method. Based on the DOE method, it is observed that the sensitivity of the drag value to the step location is higher than the speed.

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The Design of Yacht Sailplans for Maximal Upwind Speed

10.5957/csys-1995-001 ◽

1995 ◽

Author(s):

Sandy Day

Keyword(s):

Ad Hoc ◽

Structural Integrity ◽

Point Of View ◽

Hydrodynamic Resistance ◽

Viscous Effects ◽

Hull Form ◽

Induced Drag ◽

Hull Forms ◽

Prediction Approach ◽

Selection Of

A great deal of research, both computational and experiment based, has been carried out on the optimisation of hull geometry for minimal hydrodynamic resistance; however, rather less effort has been expended on the equivalent problem of optimising the sailplan geometry. The goals of the optimisation procedures which have been adopted for sail optimisation are somewhat diverse; some researchers have concentrated on the maximisation of aerodynamic drive force, with or without constraints on heeling moment, whilst other approaches have included simple representations of hydrodynamic sideforce and induced drag. Much of the work has concentrated on optimisation of the distribution of aerodynamic lift over the sailplan without specifying how the lift distribution may be achieved in practice if indeed the lift distribution can be obtained within the practical constraints of conventional rig technology. It is argued here that, from the point of view of yacht design, an appropriate goal for the optimisation is the selection of the sailplan geometry which yields the best performance for a given hull form over a suitably weighted range of windspeeds. In this work, the aspect of performance considered as being of primary importance is upwind speed. A method is presented by which the principal dimensions of the rig - luff length, foot length etc. - may be chosen so as to maximise upwind or close reaching speed for a particular yacht in a given wind strength. The aerodynamic performance of the rig is predicted using a non-linear vortex lattice model; viscous effects, including the effect of the mast, are included using an ad hoc approach based on two dimensional experiment data. The hydrodynamics and hydrostatics of the hull are obtained using a performance prediction approach based on the well known Delft yacht hull series. Optimisation of the rig geometry is carried out using a stochastic technique known as a structured genetic algorithm. Results are presented for two variations on the sloop rig; the first employs a mainsail with an essentially triangular planform, whilst the second allows the inclusion of a substantial roach, leading to sails of the form normally associated with full length battens. The hull forms considered include typical examples of both modem and slightly older racing yachts. The sensitivity of the geometries obtained to constraints unrelated to upwind speed - such as structural integrity or offwind sail carrying capability - is also illustrated.

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.311-313.2389 ◽

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.

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High-speed brightfield 3-D imaging and 3-D image analysis of thick and overlapped cell clusters in cytological preparations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100168827 ◽

1994 ◽

Vol 52 ◽

pp. 218-219

Author(s):

Robert W. Mackin

Keyword(s):

Image Analysis ◽

High Speed ◽

Three Dimensional ◽

Image Data ◽

Ccd Camera ◽

Objective Lens ◽

Array Processor ◽

Vaginal Smears ◽

Low Contrast ◽

Computer Controlled

This paper presents two advances towards the automated three-dimensional (3-D) analysis of thick and heavily-overlapped regions in cytological preparations such as cervical/vaginal smears. First, a high speed 3-D brightfield microscope has been developed, allowing the acquisition of image data at speeds approaching 30 optical slices per second. Second, algorithms have been developed to detect and segment nuclei in spite of the extremely high image variability and low contrast typical of such regions. The analysis of such regions is inherently a 3-D problem that cannot be solved reliably with conventional 2-D imaging and image analysis methods.High-Speed 3-D imaging of the specimen is accomplished by moving the specimen axially relative to the objective lens of a standard microscope (Zeiss) at a speed of 30 steps per second, where the stepsize is adjustable from 0.2 - 5μm. The specimen is mounted on a computer-controlled, piezoelectric microstage (Burleigh PZS-100, 68/μm displacement). At each step, an optical slice is acquired using a CCD camera (SONY XC-11/71 IP, Dalsa CA-D1-0256, and CA-D2-0512 have been used) connected to a 4-node array processor system based on the Intel i860 chip.

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