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Tuesday, October 27, 2009

Delftship Drawing Modes for Naval Architects

Delftship is light yet powerful ship design software for naval architects capable of developing hull form or ship's lines plan and calculating hydrostatic properties. In my previous post, I discussed about how to design the main deck of a yacht using extrude function of the software.
Now I am going to discuss various drawing modes which the Delftship has to visualize the ship drawings in three dimensional views. On page 14 of Delftship user manual book we can read that the computer ship design software provides five drawing modes which ship designers can use to see the fairness and the 3 dimensional forms of their design.

After designing the hull form of the yacht, I want to visualize it on computer screen in 3D views. The first view is Wireframe. This is the view which naval architects can use to see the boat or ship through its points, lines and edges. The designed ship is presented only with lines. Press Ctrl-W and you will see the yacht that looks like the following drawing

delftship-yacht-3D-1.jpg

To further explore the Delftship design capability, we can visualize our yacht in Shade drawing mode. The surfaces of our yacht will be represented in solid color, lines and curves. The submerge surfaces of the boat will have different color. Press Ctrl-F to see the boat in Shade Mode.

delftship-yacht-3D-2.jpg

Naval architects can check whether the surfaces of their design are developable or not. This can be done by pressing Ctrl-D. The boat will look like the following

delftship-yacht-3D-3.jpg

The above view is needed by the shipbuilder to see whether the hull which naval architects develop can be manufactured or not. Most of the ships' hulls have curve forms in two directions. These are also called compound curves. Naval architects need to design the hull form of the boat in a way that the surface will look green to enable plate development.

The next drawing view to visualize the yacht is the Gaussian curvature. Press the Ctrl-G, then the drawing of the boat will look like the one below:

delftship-yacht-3D-4.jpg

The Gaussian curvature is used to check the fairness of the hull. Please read page 14 of the Delftship user manual to understand more about this view. The last drawing mode is Zebra shading. To activate it, press Ctrl -E.

Computer ship design software such as Maxsurf, Delftship, Rhinoceros and Autoship are powerful in helping naval architects in visualizing their designs in 3D forms to ship owners. These software have greatly shorten the drawing or design time period naval architects usually spend when executing it manually. by Charles Roring.

Saturday, October 17, 2009

Ship’s Displacement Calculation using Simpson’s Rule

Before we begin to calculate displacement of a ship, please watch the following video to understand the basic theory of how Simpson's rule is applied in calculating areas of curves.





Displacement of a ship is the volume of sea or fresh water displaced by the ship when floating. The specific weight of the seawater is heavier than freshwater. When a ship sails from the sea into a river, her draft increases. The volume of the displaced water is the same as the volume of the immersed hull of the ship. To calculate the volume of the immersed hull, first, we must calculate the several equidistantly spaced waterplane areas from the keel to the designed load waterline.

Please, read my previous post on Boat's Waterplane Area Calculation Using Simpson's Rule which I uploaded on this Naval Architecture blog yesterday.
The method for calculating the displacement volume is the same as the one used in calculating waterplane area. All naval architects are familiar with Simpson's rule. 
Now, all the design and calculation of ship forms can be executed using such computer software as Delftship, and Maxsurf or Orca 3D (a plugin of Rhinoceros 3D modelling software for naval architecture). But all students of naval architects must perform semi-manual calculation using Microsoft Excel or other spreadsheet software to help them understand the whole philosophy of hydrostatic calculations of a ship.  

Please, read the classic Basic Ship Theory to know more about Simpson's Rules and their application in ship design. by Charles Roring

HIKING TOUR IN MINAHASA HIGHLAND
The highland of Minahasa is a great destination for visitors who like hiking. The tour that I offer will combine hiking with sightseeing, and wildlife watching especially for birds and butterflies. 
The hiking tour will be conducted across villages and farmland as well as forest and rice fields. Along the hiking trails, visitors will be able to see natural scenery, enjoy watching a lot of species of birds such as Sulawesi Cuckoo Dove, White-eyed Drongo, Sulawesi Drongo, Sulawesi Pygmy Hanging Parrot, Collared Kingfisher, White-breasted Woodswallow, Black-naped Oriole, Sahul Sunbird, Crimson Sunbird, Black-crowned White-eye, Mountain (Warbling White-eye), Chestnut Munia, Black-faced Munia, Scaly-breasted Munia, Eastern Yellow Wagtail, White-breasted Woodswallow and a lot more. To do birdwatching or wildlife watching tour participants need to bring their own binoculars and camera. Rain poncho, good sport shoes and hiking bag will be needed. The pace of walking will not be fast because we will enjoy scenery of the hills, valleys and the agricultural areas. 
Please, book your trip by sending whatsapp message to my whatsapp: +6281332245180 or by email to: peace4wp@gmail.com.
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