Monday, February 7, 2011

wayang kulit

When you spend the night in Yogyakarta while enjoying leather puppet show, it will feel vivid. The melodious rhythm of the gamelan in harmony with the voice of the female singers will not let you fall asleep. The story presented by the dalang as the puppeteer as well as the storyteller will bring you into being one of the characters in the story. You will soon learn the greatness of Javanese culture in the past.




Leather puppet show is a performance art that has been more than half a millennium of age. Its presence has its own story, in relation with the entrance of Javanese Islam. One of the Wali Songo or the nine pious leaders who spread Islam in Java created the puppet by adopting Wayang Beber or Beber Puppet that grew during the triumph of Hindu-Buddha. Such an adoption was done since leather puppet had been attached to Javanese people so that it became the proper media to spread Islam, while Islam prohibited plastic arts. Consequently, leather puppet was made in order for people to be able to see shadow.

Leather puppet show is done by the puppeteer who is also the storyteller who is possibly considered the best entertainer in the world. All the night, he plays all the characters of the leather puppets forming human characters made from buffalo skin decorated with motif as the product of leather carving. He has to change the voice character, switch the intonation, produce humor and even sing. In order to make the atmosphere vivid, the storyteller is assisted by musicians who play gamelan - the traditional Javanese music instruments - and the female singers called sinden who sing Javanese songs.

The total characters in leather puppet show number in the hundreds. The puppets that are not played are stuck in banana stem that is placed close to the storyteller. While being played, the puppets will look as shadow from rear view of the white screen in front of the storyteller. The shadow is created by the light from the oil lamp placed at the upper rear of the storyteller that is cut off by the puppets being played on the screen.



Each puppet performance presents different story or act. The act variations are divided into four categories namely lakon pakem, lakon carangan, lakon gubahan, and lakon karangan. Lakon pakem is the standard story that entirely originates from leather puppet literature while lakon carangan is only the main story that also refers to the leather puppet literature. Lakon gubahan does not origin from the leather puppet stories but it uses the places in accordance with leather puppet literature; lakon karangan is entirely a free story.

The stories in the leather puppet originated from some old books such as Ramayana, Mahabharata, Pustaka Raja Purwa and Purwakanda. Now, there are some books containing lakon gubahan and karangan that have been hundreds years to be liked by the society such as Abimanyu Kerem, Doraweca, Suryatmaja Maling and so on. Among the old books, Purwakanda book is most often used by the puppeteers from Yogyakarta Kingdom.

The leather puppet show begins when the dalang takes out a puppet in the shape of a mountain called gunungan. A nightlong leather puppet show in Yogyakarta style is divided into 3 scenes with 7 jejeran or acts and 7 war acts. The first scene, called pathet lasem, has 3 jejeran and 2 acts of war accompanied by pathet lasem Javanese musical composition. Pathet Sanga as the second scene has 2 jejeran and 2 war acts, while Pathet Manyura as the second scene has 2 jejeran and 3 war acts. One of the scenes that most spectators mostly wait is gara-gara that presents typical Javanese humor.

Sasono Hinggil that is located in the south square is the place that very often performs nightlong leather puppet shows. Usually, the performances are done on the second and fourth weeks, beginning at 09.00 p.m. Another place for leather puppet performance is Bangsal Sri Manganti in the complex of Yogyakarta Kingdom. The leather puppet performance in that place is done on Saturdays, beginning at 10.00 a.m. for two hours at Rp.5,000 for the ticket entrance.





Friday, January 28, 2011

Is the Oasis of the Seas Cruise Ship safe for the marine environment?

The Oasis of the Seas and many other cruise ships have often been accused by environmentalists of polluting the ocean. It is understandable that the sea and the beautiful coral reef is a fragile marine environment. Organic and inorganic wastes can cause harmful impact to fish and animals that live in the coral reef areas.

Passengers traveling on Oasis of the Seas and other cruise ships should be well informed that they must not throw plastic wastes into the sea. Naval architects who designed ships know that they need to add sewage water processing plant inside the shipboard systems so that the sewage water can easily be decomposed by tiny marine animals that do the job.
As a matter of fact, cruise industries and other merchant ship operators are not the only ones that should be accused of polluting the environment. Most of the plastic wastes that are now drifting on the open seas come from coastal cities and towns in all continents of the earth. To stop marine pollution is to teach city and town dwellers to stop throwing their garbage to the sea.


Everyday millions of tons of domestic and industrial wastes are flowing to the sea from coastal cities around the globe. If these wastes can be recycled into other useful products then the marine environment especially the coral reefs will be in better condition.

Naval architects, marine engineers and operators of cruise ships have done their best to preserve the coral reef and marine environment. We earn money from exploiting the sea, so we know we must not destroy it.

It is also the responsibility of authorities of coastal cities and towns to stop wastes from flowing into the sea. They have to build recycling plants to process the wastes so that the burden which tiny marine animals have to do to neutralize the pollutants will be lighter.  by Charles Roring





Thursday, January 27, 2011

Can Archicad be used in ship design?

Can I use Archicad to design marine structure such as cruise ship the Oasis of the Seas? Archicad is a BIM software that is usually used by architects for designing houses, and buildings. The latest version is Archicad 14. I personally used to try the software to design simple floor plan for a small house. What I really like about this cad software is that we can create 2D drawings simultaneously with the 3D drawings of the house that we are designing. To visualize our concept house from 2D to 3D, we only need to click view in 3D and within a few seconds we can see how the house will look like. Archicad also has a lot of items in its library from furniture items such as tables, chairs and beds to home construction components such as windows, doors and stairs. Another software that is the competitor of Archicad is Revit Architecture. Revit is developed by Autodesk a giant CAD software company whereas Archicad is by Graphisoft.

After studying the Archicad tutorials for a few months, I conclude that this BIM software can only be used for visualising the interior of ship. It is not suitable for designing hull form due to various technical aspects such as resistance and propulsion, hydrostatic and stability calculation that Archicad does not have. Archicad can calculate how much material that will be needed, for example, for building a wooden house in cubic meter. But it cannot calculate that center of gravity of the ship and center of buoyancy of the submerged hull of a vessel. Although Archicad can create very beautiful interior design of a suite room of a cruise ship such as the Oasis of the Seas or the Allure of the Seas, it is lack of features that are vital in ship design.

So, if you are asked to design the interior part of a cruise ship, then it is ok to use Archicad. But if you are asked to do the basic design of a hull form including her hydrostatic and resitance as well as propulsion properties, then I must recommend other software that can do the job for you. They are Maxsurf, Delfship or CATIA. If you don't want to spend money on buying the license of the software, an alternative solution is Freeship. Delftship and Freeship have similar interface. The professional version of Delftship has more complicated features for calculating damaged stability of a ship. I personally have used Delftship and written some tutorials or explanation in this blog. You can find them in this blog. I like Delfship because although its size is small it can be used to create hull form complete with the hydrostatic feature of the ship.  by Charles Roring

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Tuesday, January 25, 2011

Catamaran Yachts

Catamaran is a type of high speed marine vehicle that is designed to have two identical hulls. The slender hulls of a catamaran make the speed of the boat faster compared to a mono hull boat with similar displacement. Because the boat has bigger width, its deck area is larger and suitable for placing passengers rooms, or equipment for research or defense. In recent years, the design of sailing yachts uses catamaran form for the hull type. The following Youtube video shows how a catamaran yachts powered with engines on both sides of the hull move on the surface of the water.


Catamaran yachts are now designed and built by naval architecture firms to meet the demand of pleasure boats that have higher speed with greater stability and at the same time larger deck area for passengers or guests accommodation. Because of the wider deck area a big catamaran can have rooms as spacious and as luxurious as the Oasis of the Seas rooms. Oasis of the Seas have rooms in the superstructure are stacked on port and starboard sides of the cruise ship. Typical catamaran accommodation rooms are concentrated in the superstructure that is constructed on the "bridge" between the two hulls of the boat. Catamaran also has smaller draft which makes it capable of moving in high speed in shallow water. Boats with smaller draft are not installed with controllable pitch propellers but jet foil. With jet foil, water from the bow area under the hull is sucked into a tunnel where there is a propeller there. The propeller will accelerate and propel the water out of the hull creating a reaction thrust from the water that pushes the boat to move forward.
Catamaran with small draft is a very important capability that a pleasure boat must have in order to bring its passengers to lagoon or white sandy beaches whose water depth is sometimes less than five meters. The boat can be powered with large sail as catamaran sailboat or with internal combustion engine or both. The materials for building a small size catamaran range from wood to fiberglass. Sometimes aluminum is also used. All these materials are suitable for boats. For larger boats, steel is usually used.
Naval architects can use such software as Delftship or Maxsurf to develop hull forms of catamaran. The lastest Defltship free provides hull design features but only limited to symmetrical form. Designers who plan to design catamaran or other hull whose forms are not symmetrical must buy the professional edition. BIM software such as Archicad or Revit architecture can only be used for the interior design of the ship. Archicad does not have features where naval architect can use for calculating hydrostatic as well as resistance and propulsion properties of a ship.
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