Predictions

Methods of power prediction

Experimental methods:
Model tests

Empirical methods:
Using multiple regression analysis

Statistical methods:
Specific formulation over the data base

Numerical methods:
Computational Fluid Dynamics (CFD)
Empirical-type programs, specifically for patrol boats (systematic series), as well as the program BOU, for fishing boats at preliminary stage of the project.

CEHIPAR uses wide-ranging empirical methods for displacement and planning ships.
CEHIPAR usually uses statistical procedures for power prediction, based on data from more than 2500 models covering a wide variety of ship types.

A recent development is the MJ3A procedure for power predictions for rapid displacement ships, such as ferries, corvettes, frigates, container-ships, etc.

This program introduces the evaluation of the hull forms into the prediction. Thus, the power prediction will depend not only on its main dimensions, but also on the hull shape. This method of prediction is a new development in this field. Different appendage configurations can be added to the un-appended hull prediction and obtain the changes they make to the towing power. This program makes an initial estimate of the propeller behavior and gives the BHP-RPM values for the ship within a certain speed range.

The RAPE program, developed in-house at CEHIPAR, calculates the resistance increment due to the appendages when the hull has a sonar dome (independent of the hull lines) or has struts, shafts, rudders, fins, stabilizers and/or anti-roll keels.

CEHIPAR has the most advanced commercial CFD codes that can be consulted below in the section on Numerical Hydrodynamics.