Travelling with Passenger Ships

Ave Maria Passenger Boat

Ships have been the most efficient means of travel or transportation in the world for thousands of years. After the "New World" had been found, people travelling from Europe to this New Continent with ships. Millions of people had crossed the Atlantic Ocean from and to "the New World" before the invention of airplane. And it took another twenty to fifty years before a large plane could carry some fifty to one hundred people on board crossing the Atlantic. Now people prefer to travel across the Atlantic or around the world by airplanes. For one reason, an airplane is faster than a ship.

Just because an airplane is faster than a ship, it does not mean that people have stopped travelling by ships. Until now, ships are still used as a means of transportation for goods and people. Many people like to travel by ships because they provide various activities and facilities. Inside a modern ferry, passengers can swim, watch movies, read in libraries, enjoy sunbathing and even surf on the internet. The atmosphere of relaxation is one of the reasons why passenger ships cannot completely be replaced by airplanes. Tourists in the Carribean who travel from one island to another with cruise ships have given significant economic contribution to these island countries.

KM Sinabung - a passenger ship that is owned by PELNI

The application of new propulsion systems has brought new types of ships that travel faster than their predecessors. Hydrofoil; catamaran; trimaran; and SWATH (Small Water-plane Area Twin Hull) move faster than conventional displacement ships. Although most ships are still propelled by marine screw propeller, new approach to hull designs and propulsion machinery have caused these new ship types to become the most preferable choice of short distance transportation means that connect coastal towns and cities.

In addition, the introduction of low speed diesel engine and highly skew propeller, together with the SWATH, hydrofoil and catamaran, has made travelling with ships becomes more comfortable due to low noise level and low vibration.
Cruise ships that travel around the world can stop by at remote islands and lower their boats to enable their passengers visit them. This is something that a large airplane cannot do if the island does not have airport. With around 95 percent of goods and people are still transported by ships, these marine vehicles will still play very important roles in shaping and changing human civilization for now and forever. by Charles Roring in Manokwari of West Papua. 

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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.

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

Efficient propulsion system in ships and boats

There are many factors that influence the fuel consumption of ships or boats. Naval architects know that the interaction between the propeller, the hull and the main engine greatly influences the fuel consumption of ships whether they are big or small. So, in order to obtain ships that have optimum propulsion efficiency, naval architects must design the ships with the propulsion system that are fully integrated.

This is not an easy thing to do because every propulsion unit is contradicting one to another. For example an efficient hull form must have lower block coefficient with streamlined shape that in the contrary reduce the carrying capacity of the ships or boats that are being designed. In addition, the use of diesel engine is seen as a highly efficient main engine that is now used in many ships but we must not forget that diesel engines have vibrations and exhaust gases that will not be comfortable for crews and passengers.

Besides the hull form and the main engine, the propeller plays very important role in the design of the propulsion system of a ship. Marine propeller is usually located under water at the stern of a ship or boat. If the propeller is well designed and manufactured by experts in ship's propulsion, the fuel and financial savings will be greatly significant throughout the operational years of the ships or boats. by Charles Roring. Also read: How to estimate ship's length for a new design

Sailing Across the North Pole with Boat to the New World

by Charles Roring

On this article, I am not going to talk about ship but a little about a legendary boat. There was a legend in Ireland which says that the Irish monks were the first European to land on the New World. Around one thousand years ago, an Irish boat sailed across the north-pole waters to find a new land. They used a boat whose hull was not made of wood but animal skin. I read the story about this expedition on an article of National Geographic Magazine. I forgot the year of its publication. I wonder how a small boat crossed the Atlantic. It was too dangerous to sail from Ireland to the New World with a boat that was not seaworthy. All naval architects would agree with this.

There were some Irishmen who re-built similar boat and used it to cross the icy ocean and landed on Canadian territory. They proved that the Irish monks could have been the first Europeans to find the New World. I saw that the cover picture about the story was very interesting and I drew it on a small paper. The boat had sails decorated with red-cross. I used Derwent watercolor pencils to make the drawing. It took three days to finish the drawing of the boat.

Ship rudder

Every cruise ship and cargo vessel needs at least one rudder. This is usually installed behind a propeller which is located at the stern of the ship or boat. Although we cannot see it, the functions of rudder are vital for the maneuverability of the ship. A rudder, according to page 87 of Ship Design and Performance for masters and mates, is needed
1. To keep the ship on a straight line, from Port 'A' to Port 'B.' In other words, to have good course keeping properties.

2. To turn the ship in a small turning circle diameter. In other words, to have good turning characteristics, say in confined waters.

The dimensions of a rudder are determined by the coefficient K according to the type of ship, the length between perpendiculars, and the loaded draft of the ship.

The following formula is used by naval architects to calculate the rudder area of ship. A_R = K x LBP x d (m²)

If a ship is a fast one, generally, its K value is lower. So, the rudder of high speed marine vehicles is smaller than conventional speed marine vehicles with the same displacement. Below is the coefficient K for several merchant ships. The above formula can also be used for ships with twin screw propellers.

We have to remember that rudder is not the only equipment that is available for ship's maneuvering. Most cruise ships and cargo vessels have bow thrusters to help them turning to the right or to the left.

Usually the height of a rudder is 1.75 its length. Please, see the following illustration as a guidance for naval architects when designing ship's rudder.

It is important to note that the rudder size should not be too large. If it is larger than appropriate, it will be an additional resistance for the ship itself as well as decreasing the course keeping properties of the ship.Rudder is turned by hydraulic mechanism that has been installed above it inside the stern part of the ship's hull. by Charles Roring Also read: Are cruise ships safe for the marine environment?

Cruise ship and passenger ship

Cruise and passenger ships are ships that transport people from one port to another. Although these ships look similar, they have different purposes. Cruise ships usually emphasize their services on cruising experience for passengers aboard with various facilities such as restaurants, movies, sun-deck, swimming pool, sport centers, message and spa rooms. Cruise ships, to some extent are the same as hotels. In other words, cruise ships are floating hotels for sea or ocean travelers. Therefore, many cruise ships sell round-trip tickets and have voyages that are longer than passenger ships.

Between 1800s and early 1900s, passenger ships are transport oriented ocean liners that bring passengers and goods from European ports to American ports. Millions of migrants moved from Europe to America using passenger ships. One of them is the unfortunate RMS Titanic. During that time, the faster the voyage the better the service of the ships and the higher would be the profits they could get due to the reduced operational cost for every trip.

Indonesia's state owned shipping line, PELNI, operate dozens of German made passenger ships to serve the ever growing Indonesian passengers. Indonesia has more than 17,000 island which makes it as the largest archipelago in the world.

With the advent of large passenger airplanes in 1960s, travelers switched from ships to airplanes. For transatlantic service, the passenger ships ceased their operation in 1986 whereas in many other parts of the world such as in Mediteranean Sea, the Indonesian islands, the Philipine islands, and the Pacific islands, passenger ships still play very significant role in transporting people and goods. Indonesian government, through its state owned passenger liner - PELNI, has even bought more passenger ships from Germany to meet the increasing number of people moving from one island to another. For smaller islands where the number of population is small, PELNI operates smaller passenger ships which are constructed by local shipbuilders such as PT PAL. It is the largest state-owned shipbuilding company operating from Indonesian Naval Base in Surabaya city.

Passengers and porters in Manokwari of Papua were waiting for the just arrived Indonesia's PELNI's passenger ship, MV Nggapulu. The ship can carry 3,000 passengers. The ship was built in Germany.

As the largest archipelago in the world with tens of thousands of big and small islandss, Indonesia will constantly need a lot of ships and boats to support the mobility of its people and economic activities of the country. It is not surprising to see that every new year more passenger ships are needed in this country to serve the increasing number of population. The potential market for passenger ships and RORO or ferries in Indonesia is huge compared to cruise ships due to the purchasing power parity of the people. The same situation may also be seen in the Philipines where people need more passenger ships than cruise ships. Yet both countries have potential market for cruise ships operation especially for middle to upper class citizens.

While the market for cruise ship in Asia is still small, the market for North America and Europe is still growing but with high competition. Cruise ships operators such as Holland America lines, Royal Carribean International, and Carnival Cruise Lines are launching new ships to meet the increasing number of tourists who prefer to spend their precious time on various recreational activities both on board of these luxurious floating hotels or on exotic resorts in private islands of the Carribean sea.

With the improving economic growth in Indonesia, Malaysia, Thailand, Singapore, Vietnam, and the Philipines and other ASEAN countries, the potential market for cruise ships in this region will attract cruise line operators to invest billions of US dollars and Euros in building new cruise ships. It is now a matter of time for us to see hundreds of luxurious passenger liners and cruise ships operating along the seas of South East Asia. To realize this economic and business potentials, Governments of ASEAN countries need to be approached by investors to open their market for the development of ocean tourism and traveling industry through a number of deregulation in tourism sectors of the region. by Charles Roring Also read: Stability of Cruise Ship and The effect of turbulence on propeller and safety of cruise ship

Ship Displacement and Capacity Limitation

by Charles Roring in Manokwari of West Papua of Indonesia

Ship is the product of human engineering. It is intended to transport goods and people from one island to another. Ships support the progress of human life. People trade goods to every corner of the world with ships. In the same way, people also go around the world with ships. The invention of airplanes does not replace ships as the major transporter of goods and to some extend people.

The competition in business forced ship designers or naval architects to build ships that are efficient. Therefore, they tend to design and construct ships that are bigger both in displacement and passenger capacity. Ships that carry more goods and people are effectively more efficient than small ships.

But the construction or the design of ships should not only be seen from efficiency and dead weight tonnage. There are still other factors which ship-designer and shipbuilder have to think before a final design is approved for construction. Two of them are ship's safety and environmental assessment impact. For instance, if the newly designed ship is an oil tanker with a dead weight of 500,000 ton then it will not be wise to build it due to its potential environmental impact. This giant oil tanker might face an accident at sea. Oil spill from such tanker can be difficult to overcome due to the massive amount of oil which has to be contained and collected from sea surface. If 500,000 ton of crude oil covers the surface of the sea, it will block sunlight, and choke a lot of marine animals.

Such consideration also applies to passenger ships. Cruise ships that are designed with passenger capacity of more than five thousand people might not be wise to be constructed. It might be an efficient transporter but it will be dangerous if the ship face similar accidents to Titanic. Passenger safety should also be taken into account when designers want to decide the carrying capacity of a bus, a train, and most importantly a passenger airplane. Airplane that carries more than 500 people will be potentially dangerous for the passengers if it crashes. There will always be a possibility of accident at sea, land and air to all man made structures no matter how perfect or how advanced they have been designed and constructed. Also read: Traveling with ship; and Propeller Rake and Blade Thickness Diameter Ratio

Traveling with ship

by Charles Roring in Manokwari of West Papua Indonesia

Traveling with ships or boats has been a good choice for people living near the sea for hundreds of years. Ships help people traveling from one island to another.

When passenger airplanes were introduced some one hundred years ago, the number of people traveling by ships began to decrease. In recent years, the increasing number of airplane crash makes people worried about their safety. We can see that many airline companies release reports which say that they are facing bankruptcy. The real reason for the decreasing number of passengers, which they say, is the economic downturn. However, honestly we cannot ignore the psychological effects the news about plane crash brings to TV audiences. Although most of the accidents are caused by bad weather, some people who have watched such bad news are now considering of traveling by other mode of transportations.

In recent years, travelers are now considering ships as safe mode of transportation compared to airplanes. Traveling with passenger ships can be a boring voyage especially if the journey takes more than one day.

Therefore, ship designers or naval architects must design passenger ships as comfortable and enjoyable as possible. Modern passenger ships now are identical with luxurious hotels. They have such facilities as swimming pools, sun-deck, restaurants, movies, library, fitness centers, internet café, gambling hall, shops and even conference rooms. These facilities are provided to help the passengers feel relax so that they will be able to enjoy the trip rather than feel bored or anxious when looking at the dark color of the deep sea.

Besides, providing various facilities similar to luxurious hotels, passenger ships have to be designed with the highest safety standard stipulated by classification societies such as LR, GL, NK, ABS, and DNV, to prevent accidents. Modern navigational equipment as well as inflatable rafts and boats are installed in passenger ships to protect the passengers in case if an accident happens.

Today's modern technology helps naval architects and shipyard owners to design and build ships that are fully safe for sea transportation. It is important to note that the number of ship accidents is quite low compared to plane crash in recent years.

We will see that with improved speed, and better safety measures, passenger ship will be a good alternative for traveling in short distances which only takes one or two days to reach a destination. Also read: Propeller Rake and Blade Thickness Diameter Ratio; Controllable Pitch Propellers; Material and Strength of Marine Screw Propeller

Marine Diesel Engine the most preferred propelling machinery

Marine diesel engine is now the most used prime mover of modern ships. In the past, steam reciprocating engine was widely used with coal as the fuel. Steam reciprocating engine actually is a flexible engine in terms of the type of fuel it uses. When there is no coal around, ship crews could cut trees as fuel. This happened in the past, when a ship sailed to remote islands, ship crews would use wood as fuel if they ran out of coal.

Now most shipbuilders and ship designer choose marine diesel engine as the prime mover of ships that they build or design. Diesel engine is smaller, and compact compared to steam reciprocating engine. In addition, marine diesel engine does not need large room for storing coal. Fuel oil is stored in tanks usually at the double bottom of a ship and a smaller daily tank above the engine.

The improvements in engine design has made the operation of marine diesel engine both in small and large ships fully automatic. Unlike the steam engine which needs constant manning from ship crews to feed coal into the combustion room that heats up the boiler, the marine diesel engine is controlled by ship crews only by several touching buttons or moving levers.

In the future, marine diesel engine will continue to be used with expectation that the engine will be more efficient, and emit less CO2 gas and with lower vibration. by Charles Roring in Manokwari of West Papua - Indonesia. Also read: Design constraints of propeller diameter and Propeller and ship's hull

Propeller and ship’s hull

Ship propeller and boat propeller is still considered as the most economical propelling devices for ships and boats. Other propelling devices such as paddle wheel, magnetohydrodynamic propulsion system have efficiencies that are lower than screw propeller.

Propeller designer and naval architect must understand how propeller, ship's hull, rudder and main engine interact from one to another.

Ship's Hull - The hull form of a ship influences the flow of water from the forward end of the ship to the stern where the propeller is mostly installed. The finer the hull form the faster will be the ship's speed in water. The fullness of ship's hull form is reflected by its block coefficient or C_B. Ships with higher block coefficient (0.70 to 0.98) will tend to be slow in the water. Even if the block coefficient is small (0.50-0.70), the speed of ship moving in the water can be slower due to the fouling of hull surface. Hull fouling is mostly caused by barnacles, and tube worms. If the fouling is worse, it can increase the frictional resistance of ship up to 40%.

Another way which naval architects do to reduce the resistance of ship thus increasing the speed or improving the propulsive efficiency is by adding bulbous bow to the ship. By doing this, the naval architect and propeller designer can reduce the wave making resistance of the designed ship.

Ship, hull and rudder are integral propulsion system of ships. But they will not work without a main engine inside the hull. Today, marine diesel engine is used as the prime mover of ships. The use of steam and gas turbines are only used in small number of ships due to the complexity of the design although they relatively have low vibration.

Marine diesel engine for large vessels is especially designed to have low RPM. Theoretically, the lower the RPM of a propeller, the better will be its efficiency. Modern propellers are designed and manufactured to have high skew to minimize the vibration and maximize the efficiency.

In the last few decades, the development of multi-hull ships has led to the building of catamaran, trimaran and SWATH (small water plane area twin hull) ships. These new hull types are mostly used on passenger ship, ferries, fast patrol boats and ships or boats that need high speed. by Charles Roring in Manokwari of West Papua - Indonesia. Also read: Propeller design methods; Propeller Strength Calculation; Cavitation of Marine Propeller

Rolling Period of A Ship

When I was still studying in Naval Architecture department of Pattimura University, I was told that the rolling period of a ship should be between 7 and 8 seconds. This is to ensure that passengers and crews will not suffer from sea sick if the rolling period is less than seven. It means the centre of gravity of the ship is too low creating a big righting moment that is responsible for restoring the ship into its upright position. If the rolling period is higher than 8 seconds than it will be considered not safe for the stability of the ship herself.

Sometimes if the cargo is not evenly distributed, the crews have to balance the ship by filling the ballast tanks with sea water. The ballast tanks are usually placed in the double bottom of the ship. The ballast condition improves the vertical and longitudinal center of gravity thus making the ship more stable during her voyage in the middle of the sea.

Back to the discussion of the rolling period. I remembered that there was other explanation from a book entitled Buoyancy, Stability and Steering of Ship written by Dutch Naval Architect Drs. A.R. Bakker, If I am not wrong, which said that the rolling period of a ship can be expressed in a non dimensional period number which is between seven and fourteen. I wish that I could get that book again. I have forgotten how to calculate the non-dimensional rolling period of Kemp stated in that book but I believe some naval architects still read the book as a reference material especially in the Netherlands. by Charles Roring in Manokwari of West Papua - Indonesia

Prime Mover of Passenger Ship

When designing a passenger ship, naval architects have to come to a decision whether to choose steam turbine or diesel engine as the ship's prime mover. In the past, most of the passenger ships used steam turbine as their prime mover. The choice of this kind of marine engine was based on a consideration that steam engine has relatively very low vibration. Therefore, steam engine was more suitable for passenger ships. However, steam turbine installation needs more spaces for boiler, condenser, turbines, reduction gears and piping installation.

Improvements in the design of marine diesel engines have led to the application of diesel engine to passenger ships. Marine diesel engines are specially designed to have low RPM to adapt to the diameter of the propeller. This design constraints led to the development of low speed diesel engines for big ships. The lower the speed of the main engine, the better will be the efficiency and the larger will be the diameter of the ship's propellers. In smaller ships where low speed diesel engines are not available, reduction gears are needed to lower the RPM to match it to the RPM of the propeller at its optimum efficiency.

The vibration of marine diesel engine, as the prime mover of a ship, has to be kept lower to make the ship comfortable to all the passengers and crews. If the vibration of a vessel is high, passenger will not be able to sleep well or to enjoy the cruise. Marine engineers and Naval Architects have to work hand in hand to analyze the vibration of a ship before applying damping devices such as rubber and bearings to propeller shaft and engine bed foundation. Now the use of marine diesel engines in passenger ships is a common thing. by Charles Roring in Manokwari of West Papua Indonesia

Naval Architecture books and ship design software

I just received a phone call from an old friend of mine, Yunus Kermite. He is a naval architect who works for Department of Marine and Fishery. He is responsible for assessing the gross tonnage and net tonnage of fishing boats. We talked a lot this afternoon mentioning the good old memories of our past time in department of naval architecture the University of Pattimura.

Then, I said that I was about to send him a CD containing textbooks in pdf formats such as basic ship theory, marine screw propeller and the free version of ship design software, delftship.

The number of titles is around 50. Most of them are related to ship design and ship theory. I personally still understand this subject but I don't work in shipyard. With free ship design software in my hand, I think, I will write a book or website about how to design ship hulls, and other subjects on resistance and propulsion of ships or the stability calculation of ship.

Indonesia is the largest archipelago in the world consisting of more than 17,000 islands. Ships and boats are needed to connect the islands for transporting people and goods. Therefore, the Indonesian government should invest a lot of money in developing its maritime industry. It is sad to see that many universities that have department of naval architecture and marine engineering do not get enough financial support from the government.

I hope that the opening of Departement Kelautan dan Perikanan will support the educational institutions that have such study programs as Naval Architecture and Marine Engineering.

Diving Boat General Arrangement Consideration

by Charles Roring in Manokwari of West Papua - Indonesia

As naval architects, we usually begin our project design with calculations. We tend to focus more of our attention on principal dimensions such as type of ship or boat, the length overall, breadth moulded, depth moulded and prismatic and block coefficient. It is true that such principal dimensions are needed by the ship or boat designer to carry out detailed calculations including the resistance, propulsion, structural strength and the cost of construction.

A boat type which needs special design consideration from naval architects is diving boat. Diving boat is used by scuba divers in various marine parks around the world for accessing the coral reef. Most of the corals are located in shallow sea water. Therefore, when naval architects want to design the boats, they need to consider some important factors below:

The depth of boat

Because the diving boat operates in shallow water the depth of the boat should not more than five meters. It is better to have a smaller depth so that the hull bottom, keel and the propeller will not hit coral reef.

Twin hull or catamaran

In recent days, naval architects have introduced twin hull design for diving boat. This is a very good breakthrough for safe operation of the diving boat in the marine protected areas. Besides twin hull boat or catamaran has smaller depth moulded, it also has better stability. Catamaran can go to coral reef whose depth from the sea surface is around or less than 3 meters.

Wider deck area

A diving boat needs a wider deck area which is needed by dive operators for the placement of air bottles, compressor. A wider deck area means better movement for the divers to move around.

Diving platform

This is a lower deck which is constructed at the back of the diving boat or yacht which scuba divers use to climb to the boat. Usually there is a small stair which connects the diving platform with the main deck

Small freeboard

Most diving boats have small freeboard with ladder installed on both sides of the boat. After diving, scuba divers can come up to the surface and climb the boat from port or starboard side of the boat.

Diving is a fun yet dangerous sport. Naval architects need to design a room in the boat which can be used as an "emergency hospital" in case of accidents at sea. Divers can become victims of shark. Therefore, adequate first aid equipment is needed in the boat beside the diving equipment.

There are still more factors such as the sewage system and propulsion unit which I need to explain in this article but I think I should write them in another article. Also read: Designing Lines Plan with Fastship and Fastship and Delftship for Naval Architects

Super-tanker and the risk of oil spill at sea

Super tankers have been part of oil trading since 1960s. They are responsible for delivering oil and gas from refineries or producing facilities to other ports around the world. The competition among companies and the increasing demand for oil and gas has been the driving force for the increasing size of the oil carriers.

Frequently these supertankers besides having to cross large oceans such as the Pacific and the Atlantic, they have to pass by narrow yet busy straits and ports. The availability of modern navigational equipment does not guarantee that the supertankers will be free from any risk of collision with other smaller ships or boats. It is the ships' crews who have to safely guard their ships to the unloading ports. Last year, there was a tanker accident in South Korea. Oil spill from this tanker caused huge environmental damage to the coral reef, the sea, the beach as well as the fisherman villages near the area of the accident. Early this year, a cargo vessel loaded with Portland cements, and full with fuel oil in its tanks, collided with a tug boat in Jakarta bay of Indonesia. The vessel sank and spill fuel oil into the sea. Some crews lost their lives. While beach clean up can be done immediately, the destruction in the coral reef environment takes tens or even hundreds of years to recover.

Naval architects, when designing, oil tanker are guided with rules from classification societies, marpol and state regulations. They usually design tankers that have several sections or cargo holds. Collision bulkhead is also drawn at the forward end of the ship. In addition, they also provide double bottom to ensure that the tankers are still safe in case of experiencing grounding. Double bottom, collision bulkhead and double hull are not fully safe in protecting the supertankers during incidents of collision or grounding. When a supertanker experiences severe damage on its collision bulkhead, cofferdam, and double bottom, it will definitely spill oil into the sea.

Another way that we can do to reduce the negative impact of oil spill at sea is to limit the size of supertanker. It is not wise to just follow the request of ship owner by designing 500,000 tons supertanker. Size restriction is needed to ensure that the tankers that we design will not cause massive pollution in busy ports or straights. 

by Charles Roring in Manokwari of West Papua - Indonesia

Also read: Fastship and Delftship for Naval Architects and Designing Lines Plan with Fastship