Program UliSpeed

The logical next step is the combination of UliTank and UliSail to create a velocity prediction program (VPP) that determines the equilibrium of forces and moments. There are significant differences between UliSpeed and classical VPPs. UliSpeed is based on numerical modeling instead of using empirical coefficientsThe theoretical background and a comparison with measurements on the water are described in this report. UliSpeed allows, like UliSail, the optimization of the trim parameters of the sails. There is a difference, because UliSpeed maximizes the boat speed, whereas UliSail maximizes the driving force. The optimal trim might therefore be different. If you want to use UliSpeed, you have to have a table of offsets of your boat. If this is not available, you can still use UliSail. An additional feature in UliSpeed is the computation of the added resistance in waves. The program writes several files on output with the detailed description of the sails, the forces and moments, the boat speed, the leeway, the heel angle and many more helpful results. The update 2.5 contains additional features and several bugs are fixed.

Details of the program are explained in the user's manual that can be downloaded here:
UliSpeed User's manual:           pdf

A zipped file with the executable program UliSpeed_2.5 can be downloaded here        Download UliSpeed  (click on picture)

If you need a CAD-model of your sails, created with UliSpeed, you can send an e-mail to: ulrich(at)

Start       Yachtresearch       Publications       Reports       UliLines       UliTank       UliSail       Impressum & Datenschutzerklärung