cross curves of stability

[vignesh]

Is It Possible To Do Crosscurves In Autocad Using Atwoods Formula?

[marshmat]

Vignesh,

Most of what you've posted on this forum since January has been brief, desperate requests for help with school projects.

We don't work that way around here. Professionals in other fields don't work that way either. The technical knowledge needed to produce and understand all these calculations, and to translate them into workable designs, can't be condensed into forum posts. It can't even be condensed into one textbook, which is why there are several dozen textbooks on every NA's shelf.

Come here asking "I did these calculations, they're attached, but I'm not sure what the result implies for seakeeping / performance / stability under X conditions" and you'll get some useful technical help in understanding your result. Come here asking "what codes should I be looking at while I design the engine room of X vessel for Y service in Z country" and you'll get useful help. Come here asking "how do I do stability in autocad" without any context or background, and it looks like you're trying to short-cut the process of actually learning how everything goes together. Not cool.

Take a read through Eric Sponberg's "parting shot" in this month's Professional Boatbuilder magazine for more.

[vignesh]

@marshmat,

i never meant to give me the procedure for calculating cross-curves,my question was without any naval arch software can anyone explain me how aatwoods formula be calculated ,ie, i knew u can just use gz=kn-kgsin(angle of heel) where kn=kmtsin(angle of heel)..but i guess this is only for small angle of heels ,then how can cross curves of stability can be calculated for llarge angle of heel.

p.s-:i m just doing my 2nd yr graduation in naval arch ,thought seniors here can help me.definitly getting help doing assignments ,projects ,is not my intention

[Ad Hoc]

Vignesh

It is all about understand what happens at large angles of heel.

The wall sided formulae, is used for small angles of heel. This is straight forward. BUT, what the wall sided formula assumes, is that the metacentre remains the same.

In large angles of heel, the metacentre, M, or rather the location of M, on the centreline, is not fixed, and must be calculated for each angle. The upright and inclined waterlines need not intersect on the centreline of the vessel. The location depends upon the shape of the hull.

You then ends up with the curve of metacentres.