A fundamental task of the ship designer is to develop the best possible hull form on the basis of certain known (preliminarily determined) dimensions and integrated hull form characteristics, such as ship’s length L, beam B, draft T and hull form coefficients, slenderness ratio, etc., considering the following fundamental factors/criteria:
Resistance and Propulsion in Calm Water
Particular attention should be paid to:
Superposition/tuning of the generated transverse, ship-bound wave systems, namely of the bow, the stern, and the shoulder wave systems (see Sect. 2.3.1).
Favorable/smooth flow around stern shoulders and avoidance of flow separation (causing increased eddy resistance).
Favorable/smooth incident flow to the propeller and rudder.
Comment: Besides ship’s hull form, the resistance of a ship is significantly influenced , by ship’s main dimensions L, B, and T, her displacement and its distribution, as well as the mutual relationships thereof (ratios of main dimensions, slenderness ratio). Therefore, possible mistakes in choosing the proper values for the above dimensions cannot be corrected even with very careful shaping of the vessel’s hull.
Stability/Floatability in Intact and Damage Condition: Is strongly influenced by the form of the waterplane area (CWP), the form of sections below and above still water level (SWL), the type of the stern, etc.
Seakeeping Performance/Behavior in Waves:
Particularly with regard to:
Ship motions and loads in waves
Slamming phenomena and emergence of propeller (propeller racing)
Added resistance in waves
Roll motions and dynamic stability, likely capsize/foundering in waves
Bow diving and deck wetness phenomena (green water) by high waves
The above listed phenomena are affected in addition to the main dimensions, particularly by:
Displacement (total ship’s weight and its distribution)
Coefficients CB and CP
Longitudinal center of floatation (LCF)
Sections’ form character above design waterline (particularly at the bow) and freeboard/bow height
Bow/stern form
Maneuvering Capabilities:
Concerning in particular the following ship properties:
Course keeping
Maneuverability
Influenced by:
Lateral plane projected area of ship’s hull below waterline (value of a · L · T and centroid of this area).
Volume of Holds/Cargo:
It is referring to:
Dimensions of holds’ spaces
Position of holds’ openings/hatches
Available volume of holds
It is affected particularly by:
Coefficients CB, CBD (CB at the level of D), and CM
Length of parallel body
Sections’ form/character
Construction Aspects and Cost:
Is relating to:
Simplicity and ease of construction
Construction cost
and is influenced basically by the same factors as stated above for the volume of holds (see (e)).
In the framework of development of a ship’s hull form the determination of the following quantities is additionally required:
Longitudinal position of the buoyancy center and the center of floatation
Vertical position of buoyancy center
Length of vessel’s parallel body
Length of entrance/run and angle of entrance/run (slope) of sectional area curve.
In the same context the following qualitative characteristics of the vessel’s hull are determined:
Distribution of displacement, form of sectional area curve, and shape/profile of shoulders
Character and form of sections of wetted and above waterline hull form
Character and form of the design waterline (DWL) and waterlines around DWL
Shape of the bow part of the vessel
Shape of the stern part of the vessel
Configuration of deck’s sheer and determination of freeboard height
Ship’s Hull Form
Ship Design ; Chapter : 3 ; 293-357
2014-09-16
65 pages
Article/Chapter (Book)
Electronic Resource
English
British Library Conference Proceedings | 2003
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