Protected and Unprotected Openings and Spillout Points Pages

Calc uses the openings defined on these pages when performing loading calculations, deterministic calculations and probabilistic calculations. A protected opening is one which is protected by a non-return flap, such as an air pipe. An unprotected opening is one into which progressive flooding will occur when it goes below the waterline.

Spillout points typically define the boundary of a opening which allows the contents of the compartment to spill out and sea water to flow in when a point is immersed, for example, a hopper tank in a dredger.

Note:
Spillout points require the FSM setting of the compartment to be Shift Moment to allow for compartment contents to be re-balanced throughout the calculation.

Openings and Deck Edge Points Dialog - Protected Openings Tab.

The location of each opening is given by x, y and z co-ordinates (X, Y and Z respectively, measured relative to the vessel's origin in meters or feet).

The compartment, to which a protected opening is associated, may be selected from the dropdown list in the Comp ID column.

For unprotected openings, the effect of down-flooding into the specified compartment can be realized, by selecting the Allow Stepped GZ check box on the SHIP DATA \ OPTIONS dialog. Note that an opening leading to a compartment that is damaged is ignored.

A protected opening cannot cause a step in the GZ curve. Its sole function is to restrict the assessment of the GZ curve according to certain stability regulations. The purpose therefore of specifying a compartment is merely that the opening would then be ignored if the compartment were damaged.

When the ship heels and the level of the contents would be higher than a spillout point associated with the compartment, then the contents will spillout until the level is the same as the spillout point. Also if the outside water level is higher than a spillout point, then water will flow into the compartment.

Note:
This behavior does not depend on the setting of the Allow Stepped GZ flag.