General Sheet

Ship Data Dialog - General Sheet.

Balancing Tolerances

Calc takes the geometric model and balances this for weight and buoyancy to obtain the equilibrium waterline. This is an iterative process and the Balancing Tolerances are used to control the convergence and search length for the final balanced waterline. Draft and Trim (units: meters or feet) control the solution convergence, stopping the search when the changes between subsequent iterations is less than the entered values. Max Iterations stops the calculations at the entered value preventing the program from continuing indefinitely searching for a solution. If the maximum number of iterations is reached, it means that a balanced waterline (that means, a solution) has not been reached. This will be indicated in the analysis window displayed while calculations are being performed.

When performing certain calculations (for example, in hydrostatics, loading conditions, curves) you may request to refer to extreme values of draft. If this is the case, Calc will use the Keel Thickness value (units: millimeters or inches) entered here, to redefine the reference line from which to measure the drafts (that means, the underside of keel). This is true for drafts entered by you and those reported from Calc.

Water Density

This is entered in tonnes/cubic meter or tons/cubic feet. This is the only place where the density of the surrounding fluid is entered.

Plate Thicknesses

Keel and shell thicknesses are entered in millimeters or inches. Currently, entering a value of shell thickness only affects Hydrostatics, Curves, Deadweight Scale, Launching, Loading Conditions, Deterministic and Freeboard. In these analyzes, a value of shell thickness produces an extreme value of displacement and other associated values.

Propeller

you can enter values for Aft from AP, Diameter, and Shaft Height above baseline (units: meters or feet) which define the location of the propeller, as well as the Required % Immersion (value between 0 - 100). The immersion is taken as the distance the propeller tip is below the waterline and the % Immersion is this value expressed as a proportion of the draft. If values are entered in this dialog, then the system will check for each loading calculation that the required propeller immersion has been achieved and this will be reflected in the output.

Empirical WSA

If the Empirical WSA check box has been selected/activated then the system will calculate the wetted surface area of the vessel using the Denny-Mumford formula, rather than use the value determined from the geometry model.

you can also enter a multiplication factor (to make an allowance for appendages, for instance), which is used to adjust the WSA value obtained directly from the formula.

Overhangs

The Stern overhang is the distance to the aft end of the ship from the AP. Similarly the Bow overhang is the distance from the FP to the ship's forward extremity. At the moment these values are only used to limit the frame table, but they might be used for other calculations in the future.