How do I use NavCad's aligned prediction with model test or CFD data?

What Aligned Prediction Does

Aligned prediction modifies an empirical method by anchoring it to a validated reference. The reference is a known speedresistance pair (for hull resistance) or a KT-KQ dataset (for propeller performance) derived from a model test, a CFD simulation, or a sea trial. NavCad provid a prediction grounded in physical data.

This technique is valuable when:

• The user has model test or CFD assets for the vessel or a closely similar design.
• A new loading condition or variant is being evaluated from a reference vessel.
• EEXI compliance work requires the highest fidelity speedpower curve.

Setting Up Aligned Resistance Prediction

• In the , set the Technique field to Aligned prediction.
• Select the empirical Prediction method to use as the basis that best represents the hull type.
• Define the reference ship data: click Ref ship and or CFD output.
• Run the resistance prediction. NavCad will report the aligned resistance curve .

Setting Up Aligned Series (Propeller)

For propeller performance, an Aligned series reference requires a set of KT-KQ data. This can be sourced from a towing tank open-water test, a CFD propeller analysis, or a PropElements design. In the Propulsor data entry, set Propulsor type to Aligned series and import or enter the reference propeller KT-KQ data.

For EEXI work, the aligned series should use ITTC scale correction configured to Full ITTC (as required by IMO MEPC guidelines). Custom scale corrections are also available for non-standard cases.

Related Articles

• How do I choose a resistance prediction method in NavCad?
• How do I enter propeller performance data from a towing tank test or CFD analysis into NavCad?
• What is EEXI and how does NavCad help with compliance assessment?
• How do I prepare an EEXI Technical File using NavCad?