Question:

When should I adjust the LF and/or BF?

Answer:

The LF and BF are the parameters that control the length factor and beam factor, respectively. These parameters adjust how the SEA command creates a mesh representation of your hull to compute hydrodynamic forces.

The default LF and BF are 50 and 8, respectively. These values are acceptable for most hull geometry.

Consider increasing the LF if the hull changes shape rapidly longitudinally. When this is the case, the geometry file usually requires closely spaced stations. A larger LF will help capture these changes.

Consider increasing the BF if the hull changes shape rapidly transversely. Increasing the BF will also decrease panel size, leading to theoretically more precise solutions.

Note that increasing the LF or BF will result in longer computation time, so use them sparingly. One trick is to actually dramatically decrease the LF and/or BF to reduce computation time when setting up and testing a long run. Once the run is tested and you're certain you've included all of the correct parameters, bring the LF and BF back to reasonable values and compute the final results.


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