One of the common way is to estimate the displaced volume and use the buoyancy relations. Should the manufacturer provide the empty-vessel weight ?

Thank you Elhadi I. Dekam, your contribution is much appreciated!

I would like to expand on your input:

Displacement = Lightship + Deadweight

Lightship = Steel + Outfitting + Machine + Margin

Outfitting = deadweight * coefficient/parameter(s)

Now there are several methods with which the total outfitting weight can be estimated. Those are dependent on statistical ship data, which was used to compile diagrams or calculate coefficients. The outfitting weight is then calculated by multiplying the deadweight with those coefficients or by matching the deadweight with a graph of certain ship types and reading off the outfitting weight. Sometimes, LPP and Breadth are added to the mix. But these diagrams and coefficients are often outdated, only applicable to serial produced merchant vessels like container ships or are proprietary and if a shipyard has no experience with a certain type of ship, this results in a very labourintensive design process.

So, I would like to see if it is possible to parameterize certain groups of outfitting in order to make to design process easier and estimates more acurate. But before I dive right in, I need to know if anyone else has some input on this topic.

Dear Malte Hasse,

I'd like to recommend two resources in which I believe you will find plenty of information regarding the calculation of abovementioned parameters.

1) Practical Ship Design, D.G.M Watson, Elsevier.

2) Ship Design and Construction, Thomas Lamb, Editor, SNAME.

Dear İlkay Özer Erselcan,

Thank you for your input. I will check those books out.

Does anyone have any practical information on how estimation and control of wheights (aka wheight management) is handled at a shipyard?