Cross curves

Hi John.
The cross curves produced by Archimedes are KN (m) vs heel angle and displacement.
Am I correct in assuming that KN is the transverse distance from the base line (K) to the intersection of the buoyancy force resultant with the horizontal plane through the base line at that heel angle (N)?
I could not find a definition in the user manual.
Cheers,
Peter


KN Definition

Hi Peter,

The value for KN reported in Archimedes is simply the true transverse offset of the cob from the origin of the vessel on the transverse plane (i.e. offset from the z axis).

Archimedes calculates the KN by rotating the model about the origin (X=0.00m, Z=0.00m) and then balances the hull to the required displacement (fixed trim) and reports the TCB.

Once the load balancing errors have been ironed out it is relatively easy to add free trim to this and allow full GZ curves to be created.

Festive Regards

John

jamac
Site Admin
email - info_at_naval-architecture_dot_co_dot_uk


KN definition

Hi John,
I think that is what I meant.
A diagram would be the best way to define it.
Cheers
Peter Southwood


KN Values

Hi Peter,

The following imagfe should clarify what is meant by KN's within Archimedes.

The upper cross section show a section on a vesel afloat at waterline WL1 which represent a displacement K (Te).

In this case the COB happens to lie on the vessel CL and the set up of the coordinate system means this has a value of TCB=0.00m (X Axis).

To calculate the KN at 25 Deg Archimedes roates the hull 25 Deg about the origin and then reports the TCB position on the X Axis relative to the same origin and coordinate system.

KN Definition
KN Definition

Hope this helps and any more questions, please post.

Best Regards

jamac
Site Admin
email - info_at_naval-architecture_dot_co_dot_uk


KN definition

Hi John,
That is what I thought. The diagram defines it better than words.
Cheers
Peter Southwood