Open source hydrodynamic coefficients converter and viewer for FAST


Trying to set a bridge between Nemoh and FAST, I have just released a software, BEMRosetta (, which converts hydrodynamic coefficients between different tools. In addition, it allows to visually comparing results (see enclosed screenshot for the same geometry with Wamit and Nemoh) and it includes a basic mesh viewer.

Specially for FAST users, it allows to load hydrodynamic coefficients from Nemoh and Wamit, and save them directly in HydroDyn.dat and .1, .3 .hst files.

Although the source code is included, Windows portable exes are also provided, in GUI and command line versions, to run without installation.
A full version for Linux is also available. New versions will include input from AQWA and a link to an advanced state space processor.

While a personal initiative, it will be properly maintained and improved.

If you use it and find something to improve, please let me know.

Best regards
Iñaki Zabala

PD. This is the list of formats supported:

  • BEM coefficients
    – Load
    Wamit: .out, .3sc, 3fk, .1, .3, .4, .hst
    Nemoh:, Mesh/Hydrostatics*.dat, Mesh/KH*.dat, RadiationCoefficients.tec, ExcitationForce.tec, DiffractionForce.tec, FKForce.tec, IRF.tec
    FAST-Wamit: HydroDyn.dat, .1, .3, .hst
    SeaFEM-Nemoh: .flavia.inf, RadiationCoefficients.tec, ExcitationForce.tec, DiffractionForce.tec, FKForce.tec
    AQWA (very soon)
    – Save
    Wamit: .1, .3, .hst
    FAST-Wamit: HydroDyn.dat, .1, .3, .hst
  • Mesh view
    Wamit: .gdf, pan.dat
    Nemoh: .dat

Images attached include a view of DeepCWind semisub mesh and a comparison of the added mass between Nemoh and Wamit for the same geometry.


I just wanted to say that BEMRosetta can now read AQWA files in .LIS and .AH1 formats, so from now on they can be converted to Wamit/HydroDyn format and read by FAST.

Best regards
Iñaki Zabala

BEMRosetta now includes an OpenFAST .out/.outb file reader, designed to be very easy to use.
It includes an online mode for updating the plot while the simulation is in progress.
Files may be opened by drag and drop, and parameters are filtered by name or units.
I hope you find it useful.

Hi All,
I am trying to convert WADAM.LIS file into WAMIT to be used in OpenFAST. I have been researching for solution to do this and have come across BEMRosetta. Please, can you let me know if I can convert WADAM files to WAMIT format using BEMRosetta?

Many Thanks,