statical stability

I don't think that understanding the concepts behind what is going on here is actually a problem. It's really very simple. You're interested in (primarily) the location of the centre of buoyancy; which for an arbitrary solid is the centroid of the immersed volume.

However, understanding why formulas work is also important, as this stops you using the wrong one at the wrong time.So in the derivation you posted, the theory is based on the addition and removal of a wedge-shaped volume. It is reasonable to assume that this theory ceases to be valid when the volume ceases to be wedge-shaped. You can see from inspection that the deck edge and turn of bilge will limit the applicability of this formula, and therefore working out whether the formula is valid would be a useful exercise; because as the deck-edge immerses the static stability properties will change significantly.

Hope this explains a bit further.

Tim B.

 

i already apply that method but the result is still unacceptable, maybe there are some mistake in my calculation....

what concern me is,

(1) the apply volume of wedge, it is only submerged wedge volume of both of the wedge volume???
(2) can i calculate the volume of the wedge using Simpson rule, find the area of wedge in every station using Auto CAD and apply it on Simpson...

really appreciate everybody opinion....

 

Azri,

The wedge theory is a simple but effective formula that may be applied to most commercial cargo hull shapes. To understand when you can and when you cannot use the wedge formula, it is necessary to understand how it works! As you are a student of naval architecture, you should be able to derive the wedge theory yourself, as it is a very simple formula!

I would start by doing the calculations assuming a simple rectangular ship. Try and calculate the shift of buoyancy based on the wedge shape created by the heel. This should lead to the understanding of the formula shown in the wedge theory!