Dear Readers,
This website provides information about traveling in Raja Ampat and West Papua as a whole. Tourism sector has collapsed due to the limitations of people's movements during this covid pandemic. A lot of guides have become unemployed.
Please, support me in continuing these works by sending your donation through Western Union to my address:
Leo Charles Roring
Jl. Brawijaya, samping SD Padma 1
Kompleks Missi, Manokwari 98311
Provinsi Papua Barat
After that, you could send the MTCN (Money Transfer Code Number) to my email: or to my whatsapp: +6281332245180.

Thank you,

Charles Roring

Tuesday, December 29, 2009

Phinisi a Wooden Sailing Boat from Indonesia

180px-Taopere.jpgIndonesia is the largest archipelago in the World. It has more than 17,000 islands scattered between the continents of Asia and Australia. As a maritime nation, Indonesian people have a long tradition of building boats both for transporting goods and people. One of the famous types is the Phinisi. It is a wooden sailing boat from South Sulawesi. The people there make Phinisi boat using traditional equipments and methods. In the past boats were only powered by sails. Now most of the boats have diesel engines. Here in Indonesia people call such boats as KLM (Kapal Layar Motor literally translated as Ship Sail Motor). Because of this hybrid system, Phinisi can be considered as an environmentally friendly boat.
In recent years, Western Naval Architects have given their serious attention to Phinisi. They try to modify the sailing boat from cargo oriented to pleasure one. Now Phinisi has been modified to function as yacht. Its construction system has also been adapted to conform with the standard classification rules set by BKI (Biro Klasifikasi Indonesia) or GL (Germanisher Lloyd). In addition,boatbuilders of Phinisi also install internal combustion engine (or diesel engine) to power the boat. For instance, a 36-meter Phinisi which has been powered with a 650 hp Yanmar diesel can have a service speed of 10 knots. This speed is considered fast compared to similar other Phinisi boats. The use of computer ship design software such as Maxsurf in optimizing the propulsion efficiency and hull-form does not change the construction method.
With the improvement of design, speed and quality of interior material of the Phinisi boats, we will see that yacht owners from around the world will be interested in ordering such sailing boats to travel the waters of not only Indonesia but also the Carribean, the Mediteranean and the Pacific. by Charles Roring

Monday, December 28, 2009

Naval Architecture Schools in Indonesia

180px-Ship-IMG_3429.JPGSuppose that you are interested in studying Naval Architecture and you are looking for schools that provide such study program in Indonesia. Indonesia is a maritime country but it has less than ten naval architecture schools which are located in several islands. For state owned universities I will recommend Pattimura University in Ambon city of Maluku islands, Institut Teknologi Surabaya (ITS) in Surabaya city of East Java and Hasanuddin University in Makassar city of the Province of South Sulawesi.

These universities have cooperation which they call Segitiga Biru or Blue Triangle. Experts or lecturers from the respective department of naval architecture and marine engineering meet regularly to discuss the latest development in the national shipbuilding industry.

Sometimes these universities conduct researches that are related to ship design and propulsion using the towing tank of Pattimura University or the hydrodynamic laboratory that is located in ITS. A new naval architecture study program has just been opened in the University of Diponegoro. But I don't know how far they have built their cooperation and relation with the three campuses. Pattimura University is the only department of naval architecture and marine engineering that has its own slipway that repairs boats up to thirty meters in length. This facility allows the students to experience direct dockyard works before entering bigger shipyard.

Other private universities that also offer naval architecture and marine engineering study programs are Universitas Dharma Persada in Jakarta and Hang Tuah University in Surabaya. I don't have any information about them, so, I cannot give you any explanation about them.

If you are not an Indonesian, you need to contact the deans of the universities to get more information whether you are allowed to study naval architecture there or not. Although most of the textbooks in these campus are written in English, you might need to master bahasa Indonesia (Indonesian language) before being able to join the classooms. by Charles Roring

Saturday, December 26, 2009

Beautiful Flowers from Tomohon

My sister ordered some bunches of flowers from Tomohon for decorating our Catholic church during the Christmas mass. The flowers arrived 12 hours late and they could not be used during the Christmas eve celebration. The distance the flowers had to travel was very far. From Tomohon in the Minahasa regency, her friend who bought the flowers had to bring them to Sam Ratulangie airport and handed them over to cabin crew of Batavia air. After that the flowers would be flown to Hasanuddin airport in Makassar city where it would then be transferred from the airplane to another one that would be flying to Rendani airport of Manokwari in the Province of West Papua. So, the flowers need around 8 hours flying not including the time they needed on land from the airport to the church before they could be used for decorating the altar.
Because of the late arrival of these flowers, my sister decided to use them for the New Year's eve celebration. To keep the freshness of the flowers, she put them in a number of baskets that have been filled with water. Also she put them near our bathroom to keep the temperature lower.
Flower farmers in Tomohon have exported their products to customers as far as Jakarta and Balikpapan. Although on the map the distance between Manokwari and Tomohon is not too far, there is no direct flight between these towns. Flowers have to be transported by car or Datsun trucks from Tomohon to Manado and be flown to Makassar before taking another flight to Manokwari.
Selling Flowers can be a good business especially during the economic downturn like what many people experience right now. Growing flowers can be done at backyards where unused lawns have been converted into flower patch. The favorite and expensive flowers that customers like to buy in this town are cut flowers such as red roses, orchid and possibly Adenium (mostly sold as live plants) Less expensive flowers such as Canna is also good for home interior.
When buying flowers, customers must know that beautiful flowers from high land areas may not grow well in lowland areas. So it is better to ask the vendors about the kind of flowers which are suitable for lowland. by Charles Roring
Also read: Barringtonia Asiatica beautiful but poisonous flower

Friday, December 25, 2009

Christmas Lunch

Today is Christmas day. I am spending all day at home watching television and talking with my parents, sisters and my wife. I think that we need some time to talk with our family sharing some interesting stories which we don't do during workdays. Now I am about to eat my lunch and I am happy to show you how Christmas at my home has been a great day for my family.

Perhaps some of you don't celebrate Christmas. It's okay. I hope that God will bless you all with healthy life and happiness.
Next year will be a challenging year with many opportunities that we can take to improve our living condition. We may plant a tree in front of our house as a simple resolution in fighting global warming. Or We may have planned to take a long holiday aboard a sailing yacht that will bring us to remote islands in the Pacific or the Carribean. Or you might have considered of giving up smoking as your resolution.
For me, I will try to update this blog more frequently and improve the content so that more of you will enjoy reading the posts. Happy Christmas

Wednesday, December 23, 2009

My Watercolor Painting of Two Girls Fishing At A Wooden Jetty

I made this painting to create awareness among us all about the importance of keeping our beach clean. In the painting you can see how dissappointed the girls were when they found out that it was not a fish that they caught but a worn shoe. They were sitting on a wooden jetty accompanied by a small teddy bear doll in a bright day. The background of the scenery shows a container ship sailing out of the bay to the open sea. There were three other boats in the bay. At a far distance, we could see the green hills and a light house standing at the end of the cape.
fishing-shoe.jpgWhen we go to a beach we may not find such beautiful and clean water. The sea areas around coastal big cities and towns are now covered with industrial and domestic wastes. Many of them contain chemicals that are harmful to the marine environment. While we may now work hard to fight global warming, it seems that we are not aware of the continuous destruction of coral reefs caused by the dumping of wastes to the sea. I hope that this watercolor painting can be seen as my way of presenting how beautiful the sea is and how important for us to not throwing plastics and other domestic garbages to the sea.
Title: Painting of Sisters Fishing at a Wooden Jetty; Artist: Charles Roring; Year: 2004; Media: Watercolor on cold press acid free Canson paper

Tuesday, December 22, 2009

The Largest Submarine in The World, Sentoku

During World War II, Japan built Sentoku the largest submarine in the world. This class of submarine, which was also named I-400, had hangar constructed on the upper main deck to accommodate three floatplane bombers, Aichi M6A Seiran. The submarine was reported to be 60% larger than the largest American submarine. The Imperial Japanese Navy (IJN) ordered the construction of the I-400 submarine class as their secret weapons to destroy major US cities and the Panama Canal - the main route for the US to logistically supply their troops fighting against the Japanese in the Pacific. The Japanese had suffered great loss during the marine battles in Guadalcanal, and Midway as well as land battles in the Netherlands New Guinea island. It had been planned that the launching of surprised attacks on the Panama Cannal and US big cities would stop the US from immediately supplying their troops in that region thus providing enough time for the Japanese to consolidate and strengthen their troops.

Unfortunately for the Japan, the I-400 submarines could not fulfil their mission because the US had bombed Hiroshima and Nagasaki with nuclear weapon forcing the Japanese government to surrender without any condition. Sentoku and her sisters submarines could carry aerial torpedoes, three 800 kg bombs and twelve 240 kg bombs to arm their Seiran aircrafts. The propulsion of this submarine was powered by four 3,000 hp engines with enough fuel to travel around the world 1.5 times.

Sunday, December 20, 2009

Bark Bag from Manokwari of West Papua

Tropical rainforest of West Papua has been the source of food for the indigenous people for thousands of years. It still plays an important role for the whole earth's inhabitants by converting CO2 emissions into fresh air that we breath everyday together with forests in Brazil, Borneo and other parts of the world.
In recent days, this forest is facing rapid illegal logging. Businessmen come to this island and convert the forest into large palm plantations that only give little benefits to the local people. When an area of the tropical rainforest has been cleared, various species of plants, mammals, birds and insects lose their habitat.
Last week, I and my friend went to the Table Mountain to take some bark for making traditional bags. We had to climb up several steep hills before we could find the tree that we need for making the bark bag. More than a century ago, tree barks were used by the indigenous Papuan people as textiles. They had not known how to make cotton thread and for making clothes. It was 4 p.m. when we took the bark from a small tree that would regenerate again after its trunk had been cut.
Then we decended from the Table Mountain of Manokwari. While we were in the middle of our way home we found a burnt land in the middle of this protected tropical rainforest which has just been cleared for vegetable patch by a local farmer. The indigenous people usually cut trees and burn them to clear the land of the forest to make it as their farmland. We could not do anything because we were not the forest authority.
Back to the story of bark bag. Arriving at Paul's house, I was given a seat to watch him pounding the bark to spread its fiber and make it tender. He needs three days to process such raw bark into a traditional bag.

As I don't have enough time to wait for that process, Paul asked his daughter to take the already made bark bag. Yes, it looks just a simple bag which the locals don't use anymore in their daily activities. Modern leather bags have replaced the existance of this bark bags which frequently are decorated with attractive ornaments related to local culture.
Writing the profile of Papuan artists who live in Manokwari is one of my ways to promote eco-tourism that is expected to improve their living quality the local people thus discouraging deforestation.

Saturday, December 19, 2009

Two Dolphins Swimming in the Blue Sea

Have you ever seen dolphins swimming along side a sailing boat or ship? I have experienced such scenes many times. When I was still a university student studying naval architecture in the University of Pattimura Ambon, I frequently traveled with KM Dobonsolo or KM Sirimahu to my hometown in Manokwari. They were passangers ships operated by PT. PELNI. When the ships were in the middle of the sea with no bad weather at all, usually passengers could see big fish such as dolphins swimming in a close distance. It was a wonderful experience for me and I decided that one day I had to make a drawing or painting of such scene.

Charcoal sketch of Dolphins
Dolphins are smart mammals that live in the sea. They are often considered as guardian angels for sailors who experience accident at sea. I used to hear a story which said that dolphins helped crews of capsized or sunken ship by taking them to a nearest island. I don't know if such case do exist in real life. I only know that there are circus shows about instructors who ask dolphins to give them a ride around the big pond to entertain the spectators. The fish can also do simple mathematical calculation.
For me, the best thing that we can do to the dolphins is by letting them live where they are right now. The less we disturb them the better. This is also true for the whole marine environment. By the way, I made the painting of these swimming dolphins in 2004. The media was Fabercastell watercolor pencils on French made Canson paper.

So, next time when you plan to have a vacation in the Caribbean islands or the Pacific region, don't forget to bring a telelens camera. You might encounter such rare scene.  Take some nice pictures as souvenirs for your family and friends. by Charles Roring

Thursday, December 17, 2009

Remains of Giant Clam on Tropical Rainforest of Manokwari West Papua

Could the Table Mountain of Manokwari of West Papua be a coral reef park several thousand or even million years ago? I and my friend Paul Werere, an indigenous Papuan, made a short hiking trip to a tropical rainforest located some five hundred meters at the back of my house. The locals here call it Table Mountain. There we found remains of giant clam shell (Tridacna gigas) and elkhorn shaped corals scattered around the mountain which are at 50 to 70 meters vertically measured above the sea surface. We also saw crabs swimming in the pond of spring water with physical appearances similar to their brothers that live among the mangrove forest. But we were not at the beach. We were on the mountain that is covered with large trees whose diameters range from 50 centimeters to 1.5 meters.
There have to be some explanations for why coral reef thrived in an area of a mountain far and high from the sea. The distance to the current beach is around 1 kilometer.
The first explanation will be that the ancestors of Papuan people might have taken the giant clams from the sea and ate them on the mountain. But this might not be true due to the existance of other corals that were not edible. The remains of hard corals and various large and tiny shells can still be found on this mountain.
The second explanation is that the corals and the giant clams had been swept away to the land by a giant wave or tsunami. While this answer might be possible, there has to be a maximum line where the giant wave had reached and stopped. Usually the line could be indicated by a long row of stones, corals, and other earth materials which had been carried into the land by the waves. So far we have not found such row of coral remains.
Then the third answer is that yes, the region used to be under the sea level. It means today's Manokwari town was under the sea level. Due to tectonic movements, the earth layers along the Table Mountain and the Northern Coastal Region of Papua island has been greatly pressed to emerge from the sea. That was how the mountain range along the northern coast of Papua had been formed. It could happen some several million years ago. Who knows?
Well while we are still guessing why this coral reef park thrived in this Table Mountain, I want to invite you to come to this forest to watch the birds singing and dancing, and to breath in the fresh air it produces while exploring the ancient coral reef without having to wear diving gear. by Charles Roring in Manokwari of West Papua

Also read:
Snorkeling in Arborek of Raja Ampat
Kingdom of Nemo
Snorkeling and Freediving in drop off Reef of Manokwari

Monday, December 14, 2009

The earthquake resistant wooden house of Minahasa enter the internet world

The traditional house of Minahasa has been recognized in Indonesia as one of the best earthquake resistant home construction that is suitable for tropical region. It looks beautiful especially when constructed in a village that is still fully decorated with flowers and green plants. In recent days, these wooden houses are increasingly being exported to other regions in the country and even abroad.

With the availability of internet connection in Woloan village, a major place where the traditional home builders can be found, traders of this earthquake resistant wooden houses try to expand their market by promoting their products on the internet. There are some websites that already offer these wooden houses. Potential buyers can choose the designs that they like based on the ones presented or can request custom designs from the housing company which are more suitable for their needs and climate condition where the houses will be erected.
The science of design and construction of Minahasan traditional wooden house has evolved over hundreds of years through trial and error of experiments that continues to improve the craftsmanship of the designers and builders. As a matter of fact, most of the wooden house design is not created by professional architect who got their expertise from college, not either by the use of Archicad home design software. Instead, the skills in designing and building of the houses have been passed on from generation to generation among the families of the house builders. Although the export of this type of wooden house is rising, there are concerns among the home builders to the availability of the raw materials.
The wooden house of Minahasa is mostly made of Cempaka, Lingua and Jati (tectona grandis) woods. Wood as home materials are getting scarce in the region. Home builders there now order planks and blocks from southern and central region of Celebes island. Some times they order wooden blocks from Kalimantan. This creates sensitive environmental issue such as illegal logging or irresponsible deforestation. This wooden house business can still survive if the local villagers are asked to plant trees that will become the housing materials after 30 years.
Timber frame houses are more resistant to earthquake. But the wood has to be properly treated to protect its fiber from direct contact with water. The application of varnish or paints on its surface will greatly protect the wood from decaying. In addition the standardization of sizes and types of wood used in the manufacture of wooden houses will ensure the safety of the houses. by Charles Roring in Manokwari of Papua

Tuesday, December 8, 2009

Ventilation System of Tropical House

Tropical houses are different from European houses. In cold region, houses must have good insulation to keep the indoor temperature warm during cold or winter season. Most of the houses in the sub-tropic or polar region have wood or gas stoves installed to keep warm temperature in the rooms. The case is different for tropical houses, ventilation system plays very important role in controlling the temperature of the rooms. In tropical region, sun shines all year long. The humidity is very high. Tropical houses need to have large openings such as windows and holes above doors to let the air circulate freely in and out of the houses.
Besides providing many jalousie windows, some house owners install the roof ventilators which will turn and suck the cool air into roof to cool the houses from above. City dwellers that install Air Conditioning Machines at their houses usually cover the ventilation windows and holes with transparent plastic sheets to keep the inside temperature of their houses cool. But this practice is considered not healthy because  new or fresh air cannot enter the houses.
Many tropical house owners grow trees and flower plants at the front or beside their houses to filter air and harness fresh oxygen produced by the trees to directly enter the houses during the day. This is one of the best natural ventilation systems that integrates trees as air filter and cooler. It can reduce the cost of electricity spent for operating artificial exhaust fan or Air Conditioning (AC) machines.
Although tropical houses need to have large window openings, they also need to be closed at nights to prevent mosquitoes from entering the houses. When the glass windows are closed, the air will still circulate through air holes located above the windows that are covered with mosquito nets. It means the fresh air can enter the house but the mosquitoes can't. by Charles Roring in Manokwari of Papua island.

Sunday, December 6, 2009

A Naval Architect Who Also Likes Painting and Drawing

Besides running this blog (the diary of a naval architect), I also run a home based bookstore where I sell various titles of books. As a naval architect, I am very fond of art especially drawing. I spend my pasttime drawing or painting. Sometimes I draw boat or ship not in an engineering perspective but art.
Some friends say that the drawings are very good. They suggest me to open a painting gallery. After considering their advice, this month I decide to put some of my artworks on the wall of my bookstore. So, if those of you ask what actually my profession is then I would say that I am a naval architect, an entrepreneur and an artist and a nature lover.
Dealing with the stability, resistance and propulsion calculations of ships can be stressful especially when the ship is a completely new design with unconventional hull form. So, I need to find a way to reduce my stress. Some naval architects play sports, others travel to foreign countries, and me? Drawing is my choice. It is not expensive, and it can be done at home or outdoor.
For me naval architect is passion and profession. But this will be more meaningful if it is done in an artistic way. We must remember that naval architecture is an art and science of ship design and ship building. Therefore, all naval architects must consider ships or boats or yachts that they are working on not only as products of engineering but also as artworks. by Charles Roring

Saturday, November 28, 2009

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 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 revit for house design

Monday, November 23, 2009

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.

Wednesday, November 18, 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

Tuesday, November 17, 2009

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;
Answers to problems
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.

Saturday, November 14, 2009

Ship Design

I have written several articles related to ship design calculation. If you are interested in reading them, please, check the label Ship and Boat Design of this blog. During the design process, naval architects will be required to determine such parameters as main dimensions, hull form, displacement, freeboard, depth, capacities, trim and stability, economic considerations, longitudinal and transverse strength, structural scantlings, resistance and powering, machinery, endurance, wood and outfit, lightweight and deadweight, and the material costs.
After calculating the above parameters, the next step will be the design or drawing of the ship. The first drawings will be the linesplan and the general arrangement. The detailed construction drawing will be made based on the rules and guidande provided by such classification societies as NK, ABS, LR, DNV, and etc.

Sunday, November 1, 2009

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.
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:

Saturday, October 24, 2009

Yacht design with Delftship

The following video from Youtube shows how a racing yacht moves at sea. It uses sails as prime mover. To have a faster speed, the yacht must have smaller block coefficient with streamlined hull that minimizes water resistance.

The design of ship and boat is now easier due to the availability of such computer aided ship design software as Delftship, Maxsurf, Autoship and etc. In today's post, I am going to explain how to design the main deck of a yacht using Delftship. If you haven't got the software, just go to and download it. You need to register yourself first before being able to get the free version of the Delftship.
The boat that I am about to design is the default hullform given by Delftship when I first launch Delftship's new file. The principle dimension is Length: 12 meters; Beam: 3.7 meters and the draft: 0.5 meters. After launching the new file, we will get the yacht design plans as shown on the following screenshot:
Choose the Perspective view so that we can visualize our steps of hull design in 3D form.
With the perspective view of the Delftship screen as the main window, while holding Ctrl key, please, click the edge of the boat. After that, highlight the Edit button. The pull-down menu will show up. Then select the Edge and click the Crease button. This will prevent the curving along the edge of the deck and the side hull.
After clicking the Crease, while the yellow line along the deck edge is still active, click the Edge again at the pull-down menu of the Edit and then select the Extrude option. You will be asked to enter some value.
Because we need to extrude the deck line to the centre line of the boat, we fill -1.75 meters as the half value of the yacht's breadth in the Transverse direction form.
As a result, we will get the following hull form in Plan View Window of the Delftship.
Now, we need to move the yellow edge of the deck line until it really in one axis as the center line. To do this, with Plan View of the Delftship Window is activated, click the Control points of the deck line while holding the CTRL key.
As you will see on the computer screen, the Delfship will show X Y Z coordinates. Fill in 0.00 in the Y form to move the points of the yellow deck line to the centerline of the yacht. When you have done it, press Enter, finally you will get the hull form of the yacht as shown below.
If you still haven't seen the 3D view of the boat, select Window which is located next to Help option menu. Then choose the Perspective view. After that Click the Show both sides from the pull-down menu of the Display. The remove the red lines and the control net, just click it. Now, your yacht design should look like the one above.
For those who are interested in learning yacht design, please, read Yacht Design According to Perry. It presents detailed information related to yacht. As an experienced designer, Perry explains the art and science of yacht design with many of its technical challenges in an easy to understand book. by Charles Roring

Wednesday, October 14, 2009

Naval Architecture blog in Many Languages by Google Translate

I have been running this blog since May 2007. At first, I wrote articles about anything that I encountered everyday in my daily life. After some one and a half years, I decided to focus more of my posts on such subjects as naval architecture, resistance and propulsion of ships, and marine propeller. In other words, this blog is now about ship and marine environment.
I just add Google Translate tool which you can see on the top right corner of this blog. Readers of this blog are from many countries around the world and sometimes they don't fully understand the English language which I use in writing the postst of this blog. They can just choose the language in the form and let Google Translate all the translation in seconds. I find this as one of the best tool Google provides to internet users. I hope that after adding the Google Translate tool, readers of this blog can fully enjoy the content of this blog. Thank you Google and thank you all of you for visiting and reading my writings.


Friday, October 2, 2009

Luxurious Trimaran Boat

Luxurious yachting is a special program from Luxe TV aimed at featuring beautiful boats that have exceptional design and modern propulsion equipment. Yacht owners are mostly wealthy people. They need boats that are fast, modern, beautiful and comfortable. Naval architects who design luxurious yachts always put best quality materials for hull construction and interior rooms to create an attractive and comfortable atmosphere inside the boat. Naval architecture is the art and science of ship design. So, a yacht or a boat will be an artwork too.



In the above picture, we can see how the designer of the trimaran designs the boat to look like an airplane. Its futuristic form makes the two balancing hulls at port and starboard sides appear similar to wings of airplane. This yacht or boat, with this kind of hull form, has high speed when operating. In addition, it is also fuel efficient due to lower water resistance properties that the boat has.



The inside of the boat is made of wood that has smooth surface. The naval architect who designed the boat has successfully created an impression that the boat is a home. Yacht or boat owners will feel that he or she is inside a home and not just a cabin of a boat. by Charles Roring. Also read: Trimaran and Tricycle

Wednesday, September 30, 2009

PELNI Ships in Indonesian islands

Passenger ships operated by PELNI, an Indonesian state owned passenger liner, play very important role in transporting people and goods from one to another island in Indonesia. PELNI has around 25 ships which all of them powered by marine diesel engines. Most of the passenger vessels were ordered from shipyard in Germany.


PT PELNI stands for PT Pelayaran Nasional Indonesia or National Indonesian Shipping Company. There are millions of people living along the coastal lines of thousands of islands in this country. They need passenger ships such as the ones that PELNI has to travel to other islands within the country. The sea fare is very cheap compared to the fare which cruise ships in Europe charge to their passengers.


PELNI Ships are usually named after mountains or volcanoes in Indonesia. They are KM AWU; KM Binaya, KM Bukit Raya, KM Bukit Siguntang, KM Ciremai, KM Dobonsolo, KM Dorolonda, KM Egon, KM Fudi, KM Ganda Dewata, KM Kelimutu, KM Kelud, KM Labobar, KM Lambelu, KM Lawit, KM Leuser, KM Nggapulu, KM Pangrango, KM Sagiang, KM Sinabung, KM Sirimau, KM Tatamailau, KM Tidar, KM Tilongkabila, and KM Umsini.

PELNI Ships are modern German built vessels that are specifically built for simple Indonesian passengers who do not need vacuum toilets, and card lock doors. They are not as luxurious as cruise ships in the Europe but they are very comfortable and affordable. If you are a person who is interested in traveling and meeting ordinary people (and not wealthy pensioners) across the largest archipelago in the world, then PELNI passenger ships are your perfect choice.

Indonesia has thousands of beautiful islands with beautiful white sandy beach, pristine corals, and mountains, tropical rainforest and most importantly nice and friendly people. These are the real wealth of Indonesia which is waiting for explorers like you. by Charles Roring. Also read: Passenger Ships of PELNI Lines

Saturday, September 26, 2009

Port of Tanjung Perak Surabaya Indonesia

Port of Tanjung Perak has been visited by boats and ships from around the world since the era of Majapahit kingdom hundreds of years ago. It is one of the busiest ports in Indonesia that support the economic activities of the country. Port of Tanjung Perak is located in Surabaya, a trading city in Indonesia. It is also near the biggest naval base of Indonesia, Pangkalan AL Armada Timur. As the second largest city in Indonesia, Surabaya is seen as center of commerce beside Jakarta and other big cities.



Ships carrying cargoes and passengers arrive and leave Tanjung Perak every day. Ships from other islands in Indonesia bring raw materials to Surabaya whereas ships from Surabaya bring manufactured goods to other islands. Ships that need repair will go to Dock of Surabaya whereas ship owners who need to order new ships can go to PT PAL, the largest shipbuilder in Indonesia. All of the ship repairers and shipbuilders, as well as other marine suppliers, make port of Tanjung Perak as their headquarters. In other words, Port of Surabaya is the center of Indonesian shipping and marine industry. If we visit the port, we will see hundreds of ships and boats at its harbors.


It is not surprising to see that the marine pollution in this region is high. The color of sea water is not clear blue anymore. It looks brown-bluish now. The wastes from Surabaya city and from ships all dump in Port of Tanjung Perak's waters. Concrete actions from port administrators, marine industries, ship owners and city administrators are needed to clean the sea water around the port. by Charles Roring

Thursday, September 24, 2009

Trimaran and Tricycle

In the design of high speed marine vehicle, we know that there are ship types such as Catamaran, Trimaran, or Jet Foil. Fast ship needs twin boat and trimaran to stabilize the ship when moving fast on sea surface. Trimaran especially is further improvement or development of traditional outrigger boat used by Pacific islanders when catching fish around the coastal region near their villages.


On land there is also a term called tricycle or triseda. This is a popular vehicle in Indonesia which is used by kiosk or shop owners to deliver goods to their customers. My father just bought a new one. On the picture above, one of our workers was riding it. I see from the design, it looks like a small truck but with only three tires. If at sea a trimaran-hull increases the stability of the boat at high speed, I am doubtful if tricycle or triseda has similar properties in terms of stability. Four wheels will be more stable on the road than three wheels vehicle. From the fuel consumption point of view, the tricycle is lighter and the trimaran has finer body. So they are more efficient during operation.

Sunday, September 20, 2009

Sustainable Fishing Practice by Papuan Woman

Today I am not going to talk about cutting edge fishing boat design. As naval architects, it is easy for us to deal with trawlers, purse seine, or skip jack by reading books related to this subject. There is a famous book entitled Fishing Book of the World edited by Jan Orlof Traung. The book discusses every aspect of fishing vessel design and method of catching fish. The topic of my today's post is about paintings.


Click the above painting to read the background story of the painting. Well, today I only want to present you a painting of a Papuan Woman who was catching fish using very traditional or simple method. As you can see from the picture, she uses a fishing rod and line that is made of twisted gnemon's fiber. Gnemon Gnetum is a kind of plant which mostly grows in Papua island. People also call it Melinjo. Its young leaves are cooked as delicious vegetables. Its fruits are raw material for making crackers. The bait is tied on the tip end of the line without a hook. When the fish bites the worm, she will immediately pull up the fishing rod and collect the fish in a pocket that is also made of twisted gnemon's fiber. There is no nylon or modern fishing equipment involved in this fishing practice. Or in other words, I can say that this is really a sustainable fishing practice. She does not polute the water environment. She only takes what she needs in a proper amount. There are various beautiful watercolor paintings and drawings which I am about to upload to the blog.


This above artwork is watercolor painting of Paradise bird. These paintings were made by Paul Warere a brilliant West Papuan artist whose artworks can be seen in my online Painting and Drawing Gallery. I launched the blog last week in order to promote artworks from Papuan artists as well as empowering their economy so that they can make a living from their art expertise. by Charles Roring. Also read: Watercolor pencils drawing of Papuan Catching A Bird and Watercolor pencils drawing of Papuan Drinking Enau

Thursday, September 17, 2009

Sea Travel and the Maritime Industry in Indonesia

Indonesian people have traveled from one island to another for years. Sea travel is not seen as tourists journey but business one. As the largest archipelago in the world, Indonesia has more than 17,000 islands big and small. Before the introduction of modern passenger ships from Germany by Pelni lines, the islands between Asia and Australia continents had been served mostly by small steel cargo vessels, ro-pax ferries, and thousands of traditional wooden boats.


Sea travel and maritime industry are two inter-related sectors that support the mobility of travelers and goods in Indonesia. Airplanes from tens of airline companies in Indonesia cannot replace the vital role of passenger - cargo ships that have existed in this country for years. So, although the number of flights continues to rise in many cities and towns in Indonesia, it is not enough to fulfill the needs of means of transportation to move goods and people. Ships and boats still play significant role in Indonesian islands.


The growth of population in Indonesia is around two percent every year with the current population has reached more than 220 million people. This figure puts this country as the fifth most populous nation in the world. Such a large number of people scatter around thousands of islands from Sabang to Merauke. Besides having a lot of population, Indonesia too has high economic growth.

Indonesia's high economic growth, in the middle of world financial crisis, needs the provisions of various types of ships to support it. Indonesia needs hundreds of small passenger ships to serve the mobility of the Indonesian people and cargo ships to transport goods. Big cities in Java and Sumatra needs raw materials from Kalimantan, Papua and Sulawesi islands whereas small towns in the remote islands need cargo ships to deliver manufactured products to support the economic development. by Charles Roring

Saturday, August 29, 2009

Delineating ship lines-plan and drawing human figures

All naval architects have lives other than designing ships or calculating resistance, propulsion and stability of marine vehicles. For me, my pastime activities include drawing human figures, jogging and photography. After reading complicated hydrostatic properties of ships in some naval architecture textbooks during the day, at night I prefer to make sketches of beautiful girl, birds, scenery, and color it using Derwent watercolour pencils that I bought several years ago in Gramedia bookstore of Surabaya city.

Drawing lines plan of a ship is different from drawing the body of a beautiful girl.  Drawing human figure does not need a lot of technical calculation only more practices that are needed. Ship's lines plan can only be delineated after principal dimensions have been determined from preliminary design calculation. In the past, naval architects had to draw and fair ship lines manually. The body-plan of ships or boats has to be streamlined to minimize the resistance while moving on the water. Now, computer software such as Delftship and Maxsurf is specially made to help ship designer for doing such kind of job with better accuracy.
As I have previously said in the first paragraph of this post, I am very fond of drawing human bodies especially girls. Naturally girls' figure is streamline but to draw them we don't need any complicated calculations. It is the skill level of the artist's hand that determines the quality of the drawing. Usually, before painting or coloring, I make the sketch of the girl using Staedler 2B pencil. I will draw the macro drawing first, i.e. drawing the major parts of the body such as head, arms, body, and legs. After correcting the proportions of the body, I will continue the drawing by adding details to eyes, nose, lips, fingers, and clothing ornaments. The sketch of the drawing has to be perfect before the coloring is done.
Because I use Derwent watercolour pencils to colour the girl, I have to do it little by little. After applying first layer of colour, I have to let it dry for one day and continue the coloring again. So, the finished painting takes one week to accomplish. I can do that in one day but I will get drawing results that looks rough. by Charles Roring Read: Boat building and Living tradition of the Mentawai Tribe ; Sailing Across the North Pole with Boat to the New World and How to estimate ship's length for a new design

Tuesday, August 25, 2009

Passenger Ships of PELNI Lines the safety and service

Modern passenger ships have been integrated into Indonesian maritime industry since they were first introduced into Indonesian waters in 1980s. After the ro-pax ferry KMPTampomas accident in late January 1981, PELNI - the largest passenger lines in Indonesia began to modernize its fleet of passenger ships to prevent such disaster from occurring again.
KM Nggapulu was entering Port of Manokwari
In the middle of 1980s, PELNI received new passenger ships from Meyer Werft (shipyard) of Germany into its fleet to serve major ports in Indonesian islands. Some of them are KM Kambuna, KM Kerinci, KM Umsini, and KM Rinjani. KM stands for Kapal Motor or Motor Ship. These ships each could carry around 3,000 people but during the high seasons they double the capacity to between 4,000 and 5,000 passengers given that the summer load waterline did not exceed the minimum freeboard stipulated by IMO or Classification Rules.
All the additional passengers were deck ones. This is still practiced by PELNI lines at the moment. Although it is a dangerous practice during bad weather, as long as it still adheres to the stipulated freeboard, PELNI considers that the additional number of passengers will not bring the ship into the risk of sinking.
It is not clear whether PELNI also increases the number of life jackets, boats and rafts to protect the passengers at sea. In addition, the additional passengers that PELNI ships have to carry during school holiday, Idul Fitri, Christmas and New Year seasons make the sea voyages are not comfortable.
More passengers mean more rooms, water, and food the ships should provide. In fact, passengers often complain that they run out of water to shower. The gangways and decks look dirty too during high season voyages.
Although waste streams produced by passenger ships are smaller compared to the whole amount produced by the whole world shipping industry, when not properly treated and discharged into the sea, they really threaten the marine environment.
The provisioning of modern passenger ships has restored passengers' confidence over PELNI's service. Feeling that such investment in high cost European made ships was worthy due to the profits and better safety standards the ships gave to the company, PELNI ordered more ships in 1990s.
Today there are nearly 30 passenger ships PELNI has in its fleet. It is a state owned shipping company that is intended not only to transport people but also to connect the whole territory of Indonesian islands as one undivided country. So, it is the government's policy to provide ships that support the development of national integrity of Indonesia and also to serve passengers from moving from one island to another.
When transatlantic passenger ship-liners have long been replaced by airplanes, it is amazing to see that PELNI is the only company that runs true passenger liners in fast schedules transporting a lot of people every year.