Ship Design& Engineering

References

Required:• Intro to Naval Engineering– Ch 20

Optional:• Principles of Naval Engineering– Ch 2

Introduction

• Principles of ship design• Basic ship structure, including forces• Ship structural elements• Compartment Numbering• Submarine Design• Piping Systems & Coloring

Basic Design Considerations

• Operation Employment– Mission: task or job ship is designed to perform– Armament: measure of offensive & defensive

power of ship– Protection: features designed to thwart or

minimize destructiveness of enemy attack– Maneuverability: rapid course/speed changes– Cruising range: distance a ship can travel at

cruising speed without refuel/reprovision

Basic Design Considerations

• Seaworthiness: the ship’s ability to operate in all types of weather and sea states

• Factors affecting seaworthiness– Stability: ability of ship to return to an upright position

when heeled over– Displacement: weight of the water replaced by the ship– Freeboard: vertical distance between ships deck and

the waterline– Hull shape– Beam: ship’s width at the widest point

Basic Forces Acting on Ships

• Stress– Load per unit area (psi)– Tension, compression, shear, torsion

• Strain– Deformation per unit length

• Longitudinal Bending– Sagging– Hogging

Stress

• Def’n: load a member is carrying per unit area (psi)

• Types:• Tension: axial stress exerted

by pulling• Compression: axial stress

exerted by pressure on ends• Shear: equal but opposite

forces at right angle• Torsion: stress caused by

twisting motion

Strain

• Def’n: the distortion/deformation per unit length as a result of stress

• Measured in inches per inch (in/in)

Sagging

• Condition where ship is supported more at its ends

• Compression of main deck• Tension of the bottom/keel

Hogging

• Condition where ship is supported more in its middle

• Tension of main deck• Compression of bottom/keel

Ship Structural Elements

Ship Structural Elements• Keel– Centerline backbone of ship– Runs the length of the ship

• Framing– Ribs of ship, provide structural strength -> define

form of ship– Types:• Transverse (extend outward from keel)• Longitudinal (parallel to keel, run length of ship)

Ship Structural Elements

• Bottom– Cellular region comprised of keel & framing

• Plating– Skin over framework -> rectangular steel plates

welded together

Ship Structural Elements

• Decks– “Floors” of a ship (sometimes called “levels”)– Horizontal partitions that form tiers– Main deck is uppermost complete deck

• Bulkhead– “Walls” of a ship– Horizontal partitions that form compartments– Can either be structural or non-structural (joiner)

Ship Structural Elements

• Doors– Passage between spaces on SAME level– Can be Water-Tight (sealed with “dogs”)• Individually acting v. Quick-acting

• Hatches– Passage between spaces on DIFFERENT levels– Most are water-tight boundaries

Compartment Numbering• System used for ships built after 1949• 4 main parts– Deck – Frame– Compartment– Use

ex: 5 – 32 – 0 – E

Deck Frame Compartment Use

Compartment Numbering• Deck: – Meaning: “Space is located on this deck”– Upper levels are 01,02… successively from main– Main deck is 1– Lower decks are 2,3,4… successively from main

Compartment Numbering

• Frame: – Meaning: “Forward boundary of compartment is

on or immediately aft of this frame number”– Sequential number given to transverse frames fore

to aft

Compartment Numbering• Compartment: – Indicates position of compartment relative to

centerline– Centerline compartments are “0”– Numbers follow in succession from centerline

outboard – Even numbers for Port side (2,4,6, …)– Odd numbers for Starboard side (1,3,5, …)

… 6 4 2 0 1 3 5 …

Port Centerline Starboard

Compartment Numbering• Use: – Letter that designates primary use of the space– Examples• “A”: Supply & Storage• “C”: Control (ship control or fire control)• “E”: Engineering • “F”: Fuel tank• “L”: Living • “M”: Ammunition• “T”: Trunk• “V”: Void• “W”: Water tank

Submarine Design• Hull (made of high strength steel)– Watertight envelope designed to resist

submergence pressure at CRUSH DEPTH– Inner hull (pressure hull)– Outer hull (non-pressure hull)

Submarine Design• Structural Members– Similar to surface ship but rounded for

submarine hull shape and THICKER– All levels have expansion joints (varying

submergence pressures)

Piping & Valve Numbering Systems• White• Yellow• Purple• Dark Gray• Light Gray/Tan• Blue• Light Blue• Orange

Steam Oil JP-5HP Air LP Air Chillwater Feedwater Hydraulics

• Numbering system for valves similar to that for compartments (ie: MS-1, MS-2, etc.)

Questions, Comments, Concerns?