## 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.

Yongda said...

Can I kindly check with you, what if the draft are of different values at different stations? What would be the CI value? Also I have read your article on finding of water plane area. Why do you use 2/3*F(A)*2 and not F(A)*2.Thanx

Charles Roring said...

Yongda,
The stations in the half breadth ordinates are equidistantly spaced for 2 meters as CI or Common Interval. Because the calculation is area is calculated for both sides of the ship or boat then The area of waterplane = 2/3 x Common Interval x Area Function

Unknown said...

interesting blog. It would be great if you can provide more details about it. Thanks you.

Naval Architecture