NUMERIC Units

All attributes that have the UNIT field set for the first time, were stored in previous versions as values with no specified unit. The units that were previously attributed to their values were determined by use and convention and could change from application to application, and project to project. This flexibility can no longer be supported as ‘storage units’ must be defined. Database storage units have been set to those most commonly used, but this will not be universally compatible. The UNITS NUMERIC command is introduced for compatibility:

UNITS NUM/ERIC dimension

is used to suspend unit conversions on input and output for attributes of the nominated dimension, that is:

• No conversion from the stored value will be made on output

• No unit qualifying strings will be appended to output values

• Input values with no qualifying unit strings will be stored without conversion in the database

• If input values have a unit qualifying string, a conversion factor will be applied.

This is of particular value to users who wish to continue storing and using attribute values as now, and especially when the values stored are assumed by their system to be in units that are DIFFERENT to those now being assumed by Hull & Outfitting.

The system also supports UNITS NUMERIC DISTANCE for completeness.

When a fundamental dimension’s unit is NUMERIC, all derived dimensions that use this fundamental dimension will also be treated as NUMERIC. For example, setting NUMERIC MASS will force densities and pressures to be numeric, irrespective of the currently set distance units. Derived units can have their units set to NUMERIC even if their fundamental dimensions have units set.

Weights and Masses

In the past, Hull & Outfitting has not distinguished between weight and mass; this has now changed. Densities (mass/volume) are in Kg per cu metre and the weight of objects derived from this is in Kgf.

Pressures

Pressures are in Force per unit area. Pressure units are supported but whether the pressure is absolute or relative to atmospheric pressure (Gauge Pressure) is a matter for the user to determine when he sets values. No conversion is performed.