In MOSES, forces on the system are separated into nineteen named categories:

• WEIGHT: This is the weight of a portion of the system.
• CONTENTS: The weight of ballast in compartments or fluid in an element.
• BUOYANCY: The buoyancy of a portion of the system.
• WIND: The wind force acting on a portion of the system,
• V_DRAG: The viscous drag acting on a portion of the system. This is the velocity squared term in Morison's equation, the viscous roll damping, or the viscous drag on a piece with the -CS_CURRENT option. This can be either an excitation due to wave or current, or a damping in still water.
• WAVE: This is the linear exciting force on a portion of the system.
• R_DRAG: The radiation damping due to hydrodynamics or that due to a #DRAG load attribute.
• SLAM: This is the force due to mass transfer into the system; i.e. it is the velocity time the mass flow rate term in the equations of motion.
• CORIOLIS: This is the force due to Coriolis acceleration. It also produces a "slowly varying" force.
• W_DRIFT: This is the nonlinear part of the wave force, or the slowly varying "wave drift force". In MOSES, it does not contain an approximation of the Coriolis force. This is different than most other programs.
• DEFORMATION: This is the force on a body due to deformation of the body. This only occurs when a body has generalized degrees of freedom.
• EXTRA: This is a "extra" force that can be added to produce equilibrium in a given configuration. This is useful to "cover up" modeling errors or errors in the environment.
• APPLIED: This is a true force applied to a portion of the body.
• INERTIA: This is the mass of the body times the acceleration.
• A_INERTIA: This is the added inertia times the acceleration.
• C_INERTIA: This is the inertia of the contents times the acceleration.
• FLEX_CONNECTORS: This is the force due to flexible connectors.
• RIGID_CONNECTORS: This is the force due to rigid connectors.
• TOTAL: This is the sum of all of the other contributions.

The accuracy of the computation of forces on a plate or panel depends on the shape of the panel. In particular, the results for more "compact" panels is superior to those which are "long and skinny". As a guide to the "badness" of panels, a badness measure is reported for the &SUMMARIES of panels and plates. Now, often this measure is taken as the "aspect ratio" of the panel; i.e.

     R = W/H

Where W is the width, H is the height and W > H. This is all fine and good for rectangular plates, but when these enter the water the submerged portion is rarely a rectangle.

To generalize this notion, in MOSES, we define badness as

     B = P / [ 2 sqrt(pi*A) ]  - 1.

Here P is the perimeter and A is the area. Notice that for a circle, B is zero and that for rectangular plates it increases with the increase of aspect ratio.

When added mass is computed for a panel or plate, the results from DNV-RP-C205 are used. In particular, the force computations presented there for added mass forces are tabulated as a function of B and interpolated based on the current values of B for the submerged portion of the plate.