The open-source CFD software package OpenFOAM has reached a maturity level
such that it is possible to perform seakeeping simulations using the included VOF-based free-
surface URANS (Unsteady-Reynolds-Averaged Navier-Stokes) solver (a.k.a interDyMFoam). This
paper describes results of seakeeping tests and the experiences obtained while selecting
an appropriate combination of spatial and temporal schemes for wave and seakeeping simula- tions in
a regular head sea condition. Particular attention has been paid to the accuracy level and the
convergence rate of temporal schemes Euler and CrankNicolson since an accurate tem- poral
discretization is known to be very important for wave propagations. Here the numerical results
confirm the need for at least a 2nd-order temporal scheme. To improve the stability and the
robustness of the existing CrankNicolson scheme we customized the code and performed a numerical
experiment on the modified CrankNicolson scheme where the off-centering parameter co is
non-uniformly distributed in the domain. The results show that when using a simple distri- bution
of the co parameter the stability of the CrankNicolson scheme can be restored without having to
degrade significantly the numerical order of the scheme. This new approach allows stable
simulations to be performed where the incident wave field is propagated more acceptably with a very
small decay and, at the same time, keeps the time step large enough to allow the
simulations to finish at a reasonable CPU time
