Units and Drawing Scale in Archicad

Archicad is a very powerful Building Information Modeling (BIM) Software from Graphisoft. It is increasingly being used by architects around the world. In this article I am going to explain a little about how to set units and scale prior to designing a house or a building.

If you are an Architect who lives in India, you will use SI units as project preferences for your design. But if you live in the United States, you might prefer to keep the default settings which are in Imperial Units. As a new Archicad user, you might be confused about how to change the units from the Imperial System to the International System. If this is your case, don't worry. Take a look at my following explanation:

With the Archicad BIM software running on your computer screen, locate the Option menu. After you have found and clicked it, you will see such list as Element Attributes, Element Snap, Auto Intersection, Magic Want Settings, Add-on Manager, Project Preferences and Work Environment.

Click the Project Preferences, you will see Working Units and Levels, Dimensions, Calculation Units, Construction Elements, Zones, Layout, Miscellaneous. Click Each of them to set your desired units of measurements.

After setting the SI units, you can continue to setting the drawing scale. It is very easy. Click the Document menu and then the Floor Plan Scale… You can change the scale of the drawing which is suitable for your design project and the printer or plotter size.

Archicad and Home Design

The following articles discuss Archicad tutorials and home design for architects and interior designers. At the moment the latest release from Graphisoft is Archicad 13. It is introduced with Graphisoft BIM Server to support model based team collaboration. As the number of users of this home modeling software is going up, there is a need or demand for information on how to use it. What I provide below are not meant to replace the official explanation presented by Graphisoft - the official company which has created the Archicad rather they are my personal journals which contain stories of how I study this great software.

I hope that by sharing some of the following articles, new Archicad users especially on the introductory level may find them useful for their own personal studies. I am not sure if I am able to provide more step by step Archicad tutorials in the future.

I write about anything in this blog from earthquake resistant wooden house to how to protect our tropical rainforest which is facing rapid deforestation. So, when you come again in this blog and find out that there are no new articles about Archicad then I suggest that you visit the official website of graphisoft.com There, you will find various information that is more suitable to your needs.

If after reading the following posts, you find that there are some mistakes, then please use the comment form to write some of your opinions which are very important for the corrections or improvements of these tutorials.

Before I finish this post, I would like to recommend other similar products created by Autodesk which many architects from around the world use in their home or building design projects. They are Revit Architecture, Revit MEP and REVIT Structure. Because the three BIM softwares are made by one company, they are more compatible for one another. As every software has its advantages and disadvantages, every new user of REVIT or Archicad must consult his or her needs with experienced users of each of the software to assess the right solution for his or her design needs.

ArchiCAD and Autocad

Archicad a powerful home design software

Drawing Scale and Units in Archicad

Adding Doors and Windows in Archicad Home Design

How to design roof with Archicad
The number of Archicad users is rising in Indonesia
Designing round wall room with Archicad
Designing simple bedroom with Archicad
How to draw floor plan with Archicad of Graphisoft
How to add column and beam to a house using Archicad
Dimensioning of round wall in Archicad of Graphisoft
Creating a rounded corner wall with archicad 12

Archicad and revit for house design

Archicad promotion in indonesia
Archicad 12 the best choice software for architects and interior designer

The Maritime Engineering Reference Book

A Guide to Ship Design, Construction and Operation. When I read it for the first time, I remember the volumes of the Principles of Naval Architecture which were published by the Society of Naval Architects and Marine Engineers.(SNAME). Although it has just been released in 2008 by Elsevier, most naval architects will feel that they are quite familiar with the content of this book. As a matter of fact, it is a compilation of various naval architecture books printed by the same publisher.
For instances, the Chapter 2 which discusses the various types of marine vehicle is similar to Chapter 17 on Ship Types of the Introduction to Naval Architecture written by E.C. Tupper. The Chapter 3 Flotation and stability of the book is also the same as Chapter 5 Flotation and initial stability of the above mentioned book. For Chapter 4 the Ship Structures, it is taken from Chapter 6 The Ship Girder of volume 1 of Basic Ship Theory.

If you are a practicing naval architect, you will find that Chapter 6 on Marine Engines and Auxiliary Machinery is an interesting part of the book because it might be new subject for you. This chapter is actually a subject which is more suitable for marine engineers. Yet, naval architects who work in the design office or at shipyard will need to read it because they will always deal with such problems as propulsion systems, diesel engine performance, main engines, auxiliary machinery and equipment, instrumentation and control in their every day practical jobs. Whether you are a ship designer or a naval architect who works at dockyard, you will find that this book is very suitable for you. It does not have examples and exercises which you can study to understand each subject comprehensively but it discusses all the subjects that naval architects and marine engineers must know. Chapter 10 which deals with Underwater Vehicles is mostly about ROV or Remotely Operated Vehicles. There are not any discussions about how to design, construct and operate submarines.

A naval architect from Indonesia

She is a fresh graduate from naval architecture department of Hasanuddin University. She studied ship theory, ship construction and ship design. The most memorable experience was when she had to calculate the longitudinal and vertical centers of gravity of a ship (LCG and VCG). It was a semester assignment and not many naval architecture students passed easily. She was one of the few who could do and pass the subject in first attempt. Although naval architecture is an interesting field of engineering, it seems that now she is more interested in art particularly dancing. Nadia Siregar, an Indonesian girl, began learning Papuan traditional dance in 1993 when she was still at grade 3 of elementary school. She likes dancing because she sees that Papua island has many tribes and every tribe has its own unique cultural characteristics. "They are very interesting but I only want to focus on the traditional dance," she said.

National and International Performance - Nadia is now a member of IRIANTOS Dance Group. Its chairman is George Wellem Yomaki. Their dance group has 30 members. Together with this group, Nadia has traveled across the country and even abroad to perform various Papuan dances. Some of the festivals where she and her friends performed were: Papuan Art Festival in Biak island in 2002; Multicultural Festival in Australia from 14-18 February 2004; Dance performance in Korror city of Palau islands in 2004; T heater Performance on the Exiled and Virtual Body in Makassar city from 10 to 11 August 2007; Monolog Performance of Makkunrai Project at the Societet de Harmoni building of Makassar city celebrating Kartini Day on 1 May 2008; Nusantara Cultural Carnival in Jembrana Bali in September 2008; President and Vice President of Indonesia's Campaign Declaration at the Monument of Proclamation in February 2009; Festival of Folk Theater Media on national level in Malang city of East Java, 30-31 May 2009; Nusantara Cultural Festival at the State Palace of Jakarta on 18 August 2009.

Ship Design and Performance for Masters and Mates

If you are now working in Ship design office or are now doing your ship design semester assignment in the university, then this book is suitable for you. Students and practicing Naval Architects will find that this book is very useful in helping them carrying out preliminary design calculations to obtain the principal dimensions of ships ranging from container ship to bulk carrier and passenger ship.

If you are a yacht designer then this book is not recommended for you. There is another book entitled Principles of Yacht Design written by Lars Larsson and Rolf E Eliasson that is more suitable for you. Most of the ships that are discussed in this book are displacement ships with hull material made of steel.

This ship design and Performance for Masters and Mates is divided into two main parts. Part 1 deals with Ship Design and Part 2 dicusses the Ship Performance.The followings are the detailed information about the book.

When I was still studying Naval Architecture in Pattimura University in 1996, I used Merchant Ship Design book which was written R Munro Smith and Caldwell's Screw Tug Design as a major reference for the design assignments. Although Merchant Ship Design is an old book, it is still widely read by most of students of naval architects in Indonesia due to the availability of explanations on how to develop hull form or lines plan manually without using ship's hull fairing software such as Maxsurf, Autoship, Rhino Marine, or Delftship. But now with the development of computer technology, the tedious hull fairing task has been omitted by these software.
Title: Ship Design and Performance for Masters and Mates

Author: Dr. C.B. Barrass
Publisher: Elsevier
Thickness: 265 pages, First published in 2004
Table of Contents
Acknowledgements ix
Introduction xi
Part 1 Ship Design
1 Preliminary estimates for new ships: Main Dimensions 3
2 Preliminary estimates for group weights for a new ship 17
3 Preliminary capacities for a new ship 34
4 Approximate hydrostatic particulars 40
5 Types of ship resistance 54
6 Types of ship speed 63
7 Types of power in ships 68
8 Power coefficients on ships 74
9 Preliminary design methods for a ship's propeller and rudder 82
Nomenclature for ship design and performance 91
Part 2 Ship Performance
10 Modern Merchant Ships 103
11 Ships of this Millennium 109
12 Ship Trials: a typical 'Diary of Events' 116
13 Ship Trials: speed performance on the measured mile 120
14 Ship Trials: endurance and fuel consumption 132
15 Ship Trials: manoeuvring trials and stopping characteristics 137
16 Ship Trials: residual trials 144
17 Ship squat in open water and in confined channels 148
18 Reduced ship speed and decreased propeller revolutions in shallow waters 164
19 The phenomena of Interaction of ships in confined waters 180
20 Ship vibration 191
21 Performance enhancement in ship-handling mechanisms 202
22 Improvements in propeller performance 218
Useful design and performance formulae 228
Revision one-liners for student's examination preparation 235
How to pass examinations in Maritime Studies 239
References 241
Answers to questions 243
Index 247

Ship Stability for Masters and Mates

Hydrostatics and Stability of ships are important subjects that are studied not only by naval architects but also by deck and engineering officers who are working aboard ships. The topics in this book are similar to the volume 1 of Basic Ship Theory and another ship theory book written by Russian naval scientists entitled Statics and Dynamics of the Ships.

I like this book very much because it provides a lot of worked examples ranging from simple up to complicated ones. The concept of mathematical integration using Simpsons' rules is introduced in page 68. These rules are used in most of the hydrostatics and volume calculations of ship forms.

Hydrostatic components such as form coefficients, ship displacement, center of buoyancy, center of gravity, metacenter height are discussed in the first few chapters of the book while more complicated subjects related to transverse stability, and effect of free surface of liquids on stability of ships are presented in later chapters of the book.

Although most of the ship form calculations are now executed using naval architecture and ship design software such as Maxsurf, Delftship and Fasthip, the author of the book deliberately provides samples of manual calculations to help students and practicing naval architects understand the philosophy and the theoretical foundation involved in ship theory and design.

The followings are the table of contents of the book

Preface vii

Introduction ix

Ship types and general characteristics xi

1 Forces and moments 1

2 Centroids and the centre of gravity 9

3 Density and speci®c gravity 19

4 Laws of ¯otation 22

5 Effect of density on draft and displacement 33

6 Transverse statical stability 43

7 Effect of free surface of liquids on stability 50

8 TPC and displacement curves 55

9 Form coef®cients 61

10 Simpson's Rules for areas and centroids 68

11 Final KG 94

12 Calculating KB, BM and metacentric diagrams 99

13 List 114

14 Moments of statical stability 124

15 Trim 133

16 Stability and hydrostatic curves 162

17 Increase in draft due to list 179

18 Water pressure 184

19 Combined list and trim 188

20 Calculating the effect of free surface of liquids (FSE) 192

21 Bilging and permeability 204

22 Dynamical stability 218

23 Effect of beam and freeboard on stability 224

24 Angle of loll 227

25 True mean draft 233

26 The inclining experiment 238

27 Effect of trim on tank soundings 243

28 Drydocking and grounding 246

29 Second moments of areas 256

30 Liquid pressure and thrust. Centres of pressure 266

31 Ship squat 278

32 Heel due to turning 287

33 Unresisted rolling in still water 290

34 List due to bilging side compartments 296

35 The Deadweight Scale 302

36 Interaction 305

37 Effect of change of density on draft and trim 315

38 List with zero metacentric height 319

39 The Trim and Stability book 322

40 Bending of beams 325

41 Bending of ships 340

42 Strength curves for ships 346

43 Bending and shear stresses 356

44 Simpli®ed stability information 372

Appendix I Standard abbreviations and symbols 378

Appendix II Summary of stability formulae 380

Appendix III Conversion tables 387

Appendix IV Extracts from the M.S. (Load Lines) Rules, 1968 388

Appendix V Department of Transport Syllabuses (Revised April 1995) 395

Appendix VI Specimen examination papers 401

Appendix VII Revision one-liners 429

Appendix VIII How to pass exams in Maritime Studies 432

Appendix IX Draft Surveys 434

Answers to exercises 437

Index 443

Basic Ship Theory

Basic Ship Theory were published in two volumes. The first deals with Hydrostatics and Strength of Ship whereas the second deals with Ship Dynamics and Design.

I have been reading the books since 1993 or 1994. They are easy to understand reference both for students and practicing naval architects.

Contents of volume 1:

1 Art or science? 1.1 Authorities

2 Some tools 2.1 Basic geometric concepts; 2.2 Properties of irregular shapes; 2.3 Approximate integration; 2.4 Computers; 2.5 Appriximate formulae and rules; 2.6 Statistics; 2.7 Worked examples; 2.8 Problems

3 Flotation and trim; 3.1 Flotation; 3.2 Hydrostatic data; 3.3 Worked examples; 3.4 Problems

4 Stability; 4.1 Initial stability; 4.2 Complete stability; 4.3 Dynamical stability; 4.4 Stability assessment; 4.5 Problems

5 Hazards and protection 5.1 Flooding and collision; 5.2 Safety of life at sea; 5.3 Other hazards; 5.4 Abnormal waves; 5.5 Environmental pollution; 5.6 Problems;

6 The ship girder 6.1 The standard calculation; 6.2 Material considerations; 6.3 Conclusions ; 6.4 Problems;

7 Structural design and analysis; 7.1 Stiffened plating;7.2 Panels of plating; 7.3 Frameworks; 7.4 Finite element techniques; 7.5 Realistic assessment of structral elements; 7.6 Fittings; 7.7 Problems;

8 Launching and docking; 8.1 Launching; 8.2 Docking; 8.3 Problems;

9 The ship environment and human factors 9.1 The external environment. The sea; 9.2 Waves

9.3 Climate;9.4 Physical limitations;9.5 The internal environment; 9.6 Motions; 9.7 The air

9.8 Lighting; 9.9 Vibration and noise; 9.10 Human factors; 9.11 Problems;

Bibliography

Answers to problems

Index

Contents of Volume 2

Powering of Ships: General Principles; Powering of Ships: application; Seekeeping; Maneuverability; Major ship design features; Ship design; Particular ship types

The thickness of volume 1 is 400 pages. For volume 2, it has 373 pages. The books are now published in a combined volume by the publisher to lower the price so that it can be sold or bought easily.

I like these books very much because they have many worked examples which can be solved through manual calculation or using computer spreadsheet software.

For volume 1 which deals with Ship Hydrostatics the use of computer spreadsheet software such as Microsoft Excel is highly recommended. To further your investigation on this subject, I should recommend another important book entitled Statics and Dynamics of the Ship published by Mir, now Pacific Publisher, whose authors are V Semyonov, Tyan, Shansky.

I remembered seeing, the first time, the two volumes of these Basic Ship Theory books in 1993 or 1994 in the library of Pattimura University of Maluku islands Indonesia. They were red labeled meaning that they could only be read in the room and were not available for renting.

I had to approach a staff of the library to request permission from him for photocopying them. During that years, internet was not available in my campus and the students did not know how or where to order the Basic Ship Theory books.

After long conversation and some arguments, I was then allowed to take the books out of campus to photocopy them in the downtown of Ambon city. That's what most university students in Indonesia did to be able to read the books. Why we photocopy them? The price of these two books equals to one month salary of middle level government employee in this country. So, a father must stop feeding the whole members of the family to set aside the money for his son or daughter to buy them.

I hope now that it is more affordable to students all around the world. Perhaps Longman as the publisher of Basic Ship Theory has provided the e-book or international edition versions to make the price cheaper.

Introduction to Naval Architecture

I read it for the first time in 1993 when I was still a student studying Naval Architecture in Pattimura University in Ambon city of Maluku islands Indonesia. Previously it was entitled Muckle's Naval Architecture for Marine Engineers. This book has been revised several times by its author E.C. Tupper. The latest edition of this book has Appendix B that explains how to use spreadsheet computer software for calculating hydrostatic properties of ships. This Appendix B is closely related to Chapter 4 and 5 which are the main topics that beginning students of naval architecture must understand before continuing their studies to more complicated theories.

In my opinion, the book is suitable for anybody who wants to study Naval Architecture for the first time besides similar other naval architecture books i.e. Basic Ship Theory Volume 1 and Volume 2, also written by the same author with his colleague K.J. Rawson.
The followings are the table of contents of the book Introduction to Naval Architecture
Preface to the fourth edition ix
Acknowledgements xiii

1 Introduction 1

Ships 1

Naval architecture and the naval architect 1

The impact of computers 6

2 Ship design 8

The requirements 8

Design 10

Developing the design 11

The design process 12

Some general design attributes 20

Safety 23

Summary 29

3 Definition and regulation 30

Definition 30

Displacement and tonnage 38

Regulation 40

Summary 48

4 Ship form calculations 49

Approximate integration 49

Spreadsheets 59

Summary 61

5 Flotation and initial stability 62
Equilibrium 62

Stability at small angles 66

Hydrostatic curves 74

Problems in trim and stability 76

Free surfaces 81

The inclining experiment 84

Summary 86

6 The external environment 87

Water and air 87

Wind 88

Waves 89

Wave statistics 99

Freak waves 100

Other extreme environments 101

Marine pollution 101

Summary 103

7 Stability at large angles 104
Stability curves 105

Weight movements 111

Dynamical stability 113

Stability standards 116

Flooding and damaged stability 118

Summary 127

8 Launching, docking and grounding 128

Launching 129

Docking 133

Grounding 139

Summary 142

9 Resistance 143

Fluid flow 143

Types of resistance 146

Calculation of resistance 157

Methodical series 162

Roughness 164

Form parameters and resistance 165

Model experiments 169

Full scale trials 169

Effective power 172

Summary 172

10 Propulsion 174
General principles 174

Propulsors 176

The screw propeller 178

Propeller thrust and torque 186

Presentation of propeller data 189

Hull efficiency elements 195

Cavitation 199

Other propulsor types 205

Ship trials 209

Main machinery power 214

Summary 216

11 Ship dynamics 218

The basic responses 218

Ship vibrations 224

Calculations 226

Vibration levels 230

Summary 232

12 Seakeeping 233

Seakeeping qualities 233

Ship motions 234

Presentation of motion data 236

Motions in irregular seas 237

Limiting factors 240

Overall seakeeping performance 243

Acquiring seakeeping data 244

Effect of ship form 247

Stabilization 248

Summary 252

13 Manoeuvring 253
Directional stability and control 254

Manoeuvring 255

Manoeuvring devices 261

Ship handling 269

Dynamic stability and control of submarines 272

Modifying the manoeuvring performance 273

Underwater vehicles 274

Summary 275

14 Main hull strength 276
Modes of failure 277

Nature of the ship's structure 279

Forces on a ship 280

Section modulus 289

Superstructures 294

Standard calculation results 297

Transverse strength 301

Summary 303

15 Structural elements 304

Strength of individual structural elements 304

Dynamics of longitudinal strength 311

Horizontal flexure and torsion 317

Load-shortening curves 318

Finite element analysis 321

Structural safety 322

Corrosion 324

Summary 327

16 The internal environment 328

Important factors 328

Summary 334

17 Ship types 335

Merchant ships 336

High speed craft 359

Warships 363

Summary 373

References and Further reading 375

Appendix A: Units, notation and sources 385

Appendix B: The displacement sheet and hydrostatics 391

Appendix C: Glossary of terms 414
Appendix D: The Froude notation 423
Appendix E: Questions 428

Index 437

Naval Architecture Books

While I was still studying naval architecture in Ambon city of the Maluku islands of Indonesia, I photocopied a number of ship theory books from the library of our faculty. These books might not be available anymore because they were published between 1950s and 1970s. If they are still being published. their contents might have been edited to adapt with the latest improvement in shipbuilding technology. Because most of our lecturers studied naval architecture and marine engineering in Russia during 1960s, the books that they used to teach us were written by Russian naval scientists. I still remember their titles. For ship theory, we used Statics and Dynamics of the Ships.

Here are naval architecture books that I have at this moment.

Ship Design and Performance for Masters and Mates; Dr. C.B. Barrass - Elsevier; 2004

Introduction to Naval Architecture; E.C. Tupper- Elsevier; 2004
Ship Stability for Masters and Mates fifth edition; Captain D.R. Derrett, Revised by Dr.C.B. Barrass - Butterworth Heinemann; 1999
Maritime Engineering Reference Books

Basic Ship Theory combined volume

• Volume 1 Hydrostatics and Strength; KJ Rawson; EC Tupper 2001 - Butterworth Heinemann
• Volume 2 Ship Dynamics and Design; KJ Rawson; EC Tupper 2001 - Butterworth Heinemann

Basic Principles of Ship Propulsion - MAN Diesel A/S, Frederikshavn, Denmark

Boatowner's Illustrated Electrical Handbook

Controllable Pitch Propeller - MAN Diesel A/S, Frederikshavn, Denmark

Fishing Boat Construction: 2 Building a fiberglass fishing boat

A conceptual design of a fiber reinforced plastic fishing boat for traditional fisheries in malaysia

Fuel and Financial Savings for operators of small fishing vessels

Guide to Ship Repair Estimates (in Man Hours); Don Butler - Butterworth Heinemann; 2000

Added Masses of Ship Structures by Alexandr I Korotkin - Springer

Man on the Ocean; R.M. Ballantyne (edisi html)

Marine Propellers and Propulsion second edition; John Carlton; Elsevier; 2007

Marine Design - Rhinoceros Advanced Training Series; 2003

Marine Structural Design; Yong Bai - Elsevier; 2003

Ship Design and Construction; written by a group of authorities - editor Robert Taggart - SNAME; 1980

Ship Design for Efficiency and Economy second edition; H. Sneekluth and V. Bertram - Butterworth Heinemann; 1998

Ship Handling Theory and Practice; D.J. House - Elsevier Butterworth Heinemann; 2007
Shipbuilding Technology; V.K. Dormidontov and friends, translated by J.H. Dixon - Mir Publisher 1966

Ship Hydrostatic and Stability; A.B. Biran - Butterworth Heinemann; 2003

Ships and Science - The Birth of Naval Architecture in the Scientific Revolution, 1600-1800; Larrie D. Ferreiro; The MIT Press; 2007

Fishing Boat Design: 2 V-bottom boats of planked plywood construction; FAO Rome 2004

You may ask where to get these books. If you want to buy them, you can go to Amazon.com but there are many of them which you can download from avaxhome.ws

Rules for ship and boat construction which can be downloaded from American Bureau of Shipping website

ABS Guide for Building and Classing Offshore Racing Yacht 1994

ABS Rules for Building and Classing Reinforced Plastic Vessels 1978

ABS Rules for Building and Classing Steel Vessels 2009; Part 3 Hull Construction and Equipment

Hydrostatics and Stability

Ship’s hydrostatics and stability are the first subjects which students in naval architecture study before they deal with other subjects such as resistance and propulsion, ship’s strength and ship design.
Naval architecture is art and science of ship design and construction. In dealing with hydrostatic properties of ships, naval architects have to use mathematical approaches that are not exact calculations especially in determining the area of waterplane, the displacement of the ship and the position of the center of buoyancy and center-gravity of the ship.
Although naval architecture is not an exact science, it is a science. It is one of the most complicated yet fascinating engineering fields that demand every person involved in these subjects to have high proficiency in mathematics. The number of articles related to hydrostatics and stability on this blog, if you want to read, check them at  label Ship Stability of this blog. posts are still growing. So, if you find that the topics that you are looking for are not available, please come back again next time.

Propeller and Ship Propulsion

I have written a number of articles related to resistance and propulsion of ship especially in relation to the design of marine screw propellers. You can see them at labels Marine Propeler and Resistance of Ship that you can see on the left column of this blog. Please, click the following links to read each of them. In the design of marine screw propeller, the first thing that naval architects must perform is carrying out resistance calculation. After obtaining the effective power and speed curve the next step is doing the forward calculation to obtain delivered power, shaft power and finally the brake power. The calculation will then be continued backward using the real break power (in kilowatt or horse power) obtained from the engine's brochure to obtain the shaft power and delivered horse power by considering the losses in gear box, shaft bearings, stern tube and bossing. When these have been done, the next step is executing the propeller design calculation.

Adding Knuckle Line or Hard Chine to a Boat’s Hull in Delftship

Delftship is a ship design software which enables naval architects to create, or modify the hull of a boat or a ship effortlessly. The ship can be modeled accurately in Delftship environment. In my previous article, I discussed about the drawing modes which delfship has and how to draw deck for yacht design in Delftship.

When designing high speed boat, a naval architect will design the form of the hull that is not fully displacement one. In high speed displacement form boat will face problems related to stability. So, to solve the problems, naval architects will use plane hull or semi displacement hull which has V form. In other words, the hull will not round but will have knuckle lines.

To create such hull with chines, with the Delfship program on your computer screen opens, first click the longitudinal line of a half bread hull in perspective view while you are pressing Ctrl key. Look at the above picture.

After that when the line has got yellow color, click Edit in the menu bar and select Edge. Then click the Crease option. Now, the yellow line of the hull line which we want to knuckle will be stronger.

To visualize the hard chine which we have just created for the boat's hull, in perspective view, press Ctrl - G. The computer screen will present a 3D view of the designed boat like the following.

If we want to see the underwater form of the boat, we just turn it by moving the scroll bar at the right and at the bottom of the computer screen. The boat's or ship's hull with hard chine should look like the one below:

If you do not have the program, just go to delftship.net and register your name in the website. They will give you access to the content of the Delftship website including the download link for getting the free edition of Delftship. Delftship is similar to Maxsurf, Rhino Marine, and Autoship. It can be used to create 3D forms of ship models including the hulls, superstructure, masts, rudder and other appendages. It can also calculate the hydrostatic properties and resistance of the boat or ship. by Charles Roring

The Environmental Impact of Marine Tourism

Sunbathing, snorkeling, scuba diving, wave surfing and water skiing are some of the activities that tourists typically enjoy when they go to the beach. These activities can bring positive and negative impacts to marine environment. To reduce negative impacts of tourism activities on the environments, people who work in this industry need adequate knowledge about conservation and coastal management.
Marine tourism is a business that generates big revenues during holidays and special occasions. Being a part of the tourism industry is a great way to make money because life seems like one endless holiday. Yes, it does have its downs like any other business, but for the most part, the going is good especially if you are well-established and your customers come back to give you repeat business. Marine tourism has come into its own with the advances that have been made in the field of technology. Locations that were earlier inaccessible or unsafe are now well-known tourist spots in marine environments. The seas and the coastlines of the world are much sought after destinations for tourists all over the world, and this makes marine tourism a booming industry.

But all this interest in water sports, cruises, underwater explorations and other activities that involve the marine environment are definitely having an adverse effect on marine ecosystems and animal species that live on or near the coast.

• Natural habitats are destroyed when hotels, restaurants and other entertainment and hospitality facilities are built along the coastline.
• Surrounding areas are also destroyed in order to provide access to these facilities. With the advent of roads, airports and sea ports, people begin to populate the area and drive out the natural wildlife whose habitat the area was originally.
• The level of pollution increases with the increase in population
• Essential resources like water become critical and are sometimes in shortage.
• The coastline is destroyed due to erosion and the sea also becomes polluted with effluents from hotels and other establishments in the area.
• Cruise ships produce and dump waste in mid ocean, leading to pollution in the high seas too.
• Sewage causes algae to form over coral reefs and damages and destroys them.

With all these detrimental effects, we must adopt techniques to manage the pollution and the destruction of ecosystems, not just because we need to save the environment, but because we need to save the tourism industry itself. The environment and its quality are very important if tourism is to survive and thrive; with polluted beaches and diminishing wildlife, the tourists are going to be few and far between. And when this happens, it is the end of marine tourism as we know it.
For man and nature to coexist in peace and thrive, it is up to us to ensure that we do not wreak havoc on the environment; for if we do, it will come back to haunt us in the form of global warming and climate change.
By-line:
This guest article was written by Adrienne Carlson, who regularly writes on the topic of construction management degrees . Adrienne welcomes your comments and questions at her email address: adrienne.carlson83@yahoo.com