ROLF is the principal seakeeping code used by HSVA to simulate large roll motions of monohull vessels in time domain. The algorithm treats the roll motion in a non-linear way, while the remaining degrees of freedom are calculated by a linear strip method, rendering the computation extremely fast and at the same time reliably. For many years ROLF has been successfully used by HSVA to determine the risk of parametric rolling and capsizing for our customers projects.

The code was recently extended to include the non-linear roll damping effects of actively controlled fin stabilizers and passive anti-roll tanks in the roll motion simulation. The control algorithm, the inertia and the hydraulic system of fin stabilizers - which are common in cruise ship and yacht designs – can be realistically modeled. ROLF further lets us calculate one-dimensional fluid flow in U-shaped anti-roll tanks as well as in rectangular free surface anti-roll tanks generating the stabilising moment.

These new features allow HSVA to perform accurate roll motion simulation with and without fin stabilisers and/or anti-roll tanks to give our customers valuable and realistic information on the performance of possible roll damping devices in the early design state of their projects.

The code ROLF is a module of the program package UTHLANDE, an integrated user interface to bundle hydrodynamic programs developed and financed by six German companies.

ROLF Learns Paddling and Splashing