Interface ship x

shipXFact sheet
ShipX - Ship Speed and Powering
A Program for Predicting Speed Loss in a Seaway
During the last few years MARINTEK has integrated a program for numerical calculation of involuntary speed loss in waves in the hydrodynamic workbench ShipX. the motivation for developing this software was to enable the shipX workbench environment to provide the user with the ability to calculate calm water performance as well as speed loss in waves within one product. Both of these features were implemented in the shipX Plug-In “ship speed and Powering”. the Plug-In is based on the work behind the MaRINteK products emPower (calm water resistance and propulsion) and seaway (speed loss in a seaway). When the ship encounters waves, the total resistance increases and the propeller thrust decreases. as a result, the ship cannot sustain the same forward speed as in calm water. Involuntary speed loss in waves is a result of a change in point of equilibrium between the total ship resistance and propeller thrust. speed loss components included: • Added resistance in waves (typically from ShipX Vessel Responses (Veres)) • Thrust loss due to ship motions in waves • Wind resistance speed loss calculations require a large set of input data. the engine and propeller characteristics must be known, as well
Program data flow

as the total still-water resistance and added resistance in waves. If speed loss calculations are to be performed for an irregular sea-state, the wave spectrum defining the seastate is required input. the ship motions are required for the calculation of thrust reduction in waves. the calculation of ship motions and added resistance in waves is done in the ShipX Vessel Responses (Veres) Plug-In and the results are used as input in speed-loss calculation.

In the development of shipX ship speed and Powering, a fast to use, easy-to-learn user interface has been one of the main focuses, avoiding manual editing of input files. The speed loss software is