Aluminium vessel

[pankaj.k1980]

Hii,I would like to know about the deadmass ratio,which we use in order to determine the preliminary displacement.e.g. for a passenger vessel ,
Deadmass ratio = Cd = Deadwt/(total displacement) = 0.35..
I would like to know that is it valid for only steel vessels or for aluminium vessels as well....or do we have some other empirical relations for aluminium vessel...

I would also like to know some roght estimate of aluminium that is used to make a 100 passenger vessel...

[gonzo]

Deadmass? What are you talking about? You first need a design so an estimate of materials can be done.

[PAR]

Another example of folks in dire need of a professional . . . or more aptly, folks that think they don't . . .

[pankaj.k1980]

Originally Posted by gonzo

Deadmass? What are you talking about? You first need a design so an estimate of materials can be done.

Well..deadmass ratio is an empirical relation used to determine the preliminary estimation of Lightship.....furthermore,different kind of vessels have got diffrnt deadmass ratio......I think it will help you to understand my query....rgrds

[Ad Hoc]

You seem to undertsand what 'deadmass' ratio is, so, all you have to do now is find out, what are its limits of the ratio you have been given or selected. That will give you your answer...

If you don't know or can't find it....i refer you to post #3.

[Crag Cay]

Again an interesting question seems to have been met with the usual snotty responses from some quarters.

All the deadmass ratios I have seen quoted for various types of ship have all clearly stated 'net steel mass' in the calculation. Why is it therefore not reasonable for the OP to question if the oft quoted figure for a passenger vessel (0.35) is still valid for a vessel built in aluminium? And is this ratio still valid for passenger vessels as small as 100 pers?

[gonzo]

Hey Crag Cray: Why don't you answer the question then? What is the "deadmass" of aluminum for a 100 passenger vessel?

[Crag Cay]

Gonzo, as I said in my reply, all the deadmass ratios I've seen quoted to help in the preliminary design of ships, clearly states 'net steel mass' in their formulation. Is it not unreasonable to assume that this component of the DMR will vary in a vessel constructed entirely in aluminium? (presumably by the relative masses of a steel and aluminium in the structure).

But as these 'rules of thumb' are used in the very preliminary design stages, to calculate it is a very long winded if someone knows of a suitable figure that has already been published.

I don't know of one, but then large aluminium passenger vessels are not my field. But what's the harm in asking?

[gonzo]

I have no problem with asking. I have a problem with calling us snooty. Why don't you give him an answer instead of stalling?