Ship Design

Ship Life Cycle

• Definition of Requirement• Determination of Data and Constraints• Concept Design• Preliminary Design• Contract Design• Detail Design• Production• Tests and Trials• Service• Scrapping

Design Spiral

Definition of Requirements

Definition of RequirementsLength

BreadthDepthDraught

Form

Power

Area

WeightDisplacement

General Arrangement

Range

SeakeepingManouvrability

Strength

EconomicAnalysis

Constraints(Design)

Constraints(Design Process)

COnstraints(Design Environment)

Next Design Step

Choice

Empirical Calculations

Form Selection

MachinerySelection

Ship Type

Type Ship Area/

Weight

WeatherDeckArrangement

Calculationsr

PreliminaryControl

Longitudinal Strength

Ship Life

Design Through Selection

Basic Ship Types

• Weight Critical Ships

• Volume Critical Ships

• Unit Cargo Ships

The Weight Equations (1)

)1( sLBTCB s : displacement due to shell, appendages

L: LBP or LWL

B: Breadth

T: Draught

The Weight Equations (2)

CARGOLIQUIDS

MOH

WWDW

WWWLS

where

DWLS

DW/D Ratio

DW/D Ratio

Volume m

urCBDh V

S

VVLBDCV

)1(

Curh )/KV-(VV umh VVV

Volume

Length Beam Relation

Ship Length

Critical Factors Effecting Ship Length

• Construction limitations of the shipyard (Length of slipway, port limitations, canal limitations etc)

• Structural-Regulative limitations (number of bulkheads,

• Interference of bow waves and stern waves

• L/D limitations of class societies

Breadth

• Resistance (L/B) considerations suggests minimum breadth

• Stability (B/T, B/D) considerations suggests maximum breadth

Length-Breadth Relation

Length-Breadth Relation

L130 6.5L/B

130L30 30025004

30L 0.4/

)(L..L/B

BL

Beam-Depth Relation

Beam-Draught Relation

Draught-Depth Relation

Length-Depth Relation

Block Coefficient (CB)Alexander Formula

f

k

L

VKCB 5.0

K varies between 1.03 for high speed ships to 1.12 for slow ships

• Lf : Ship length in feet

• Vk : Ship speed in knots

Block Coefficient (CB)

Hull Weight (WH)

Outfit Weight (WH)

cLBWo

Outfit Weight (WO)

Main Engine Weight

Main Engine Weight

Remainder Machinery Weight

Total MachineryWeight for Diesel-Electric Ships

Scrap Weight

Nmber of Containers