Stability 
Freeboards and inclination
measurements give important hydrostatic and stability data necessary
for determining elements of both performance and safety. The results
of a stability test gives a boat's righting moment, vertical centre
of gravity (VCG) and limit of positive stability (LPS), which with
the Stability Index (SI) can help determine a boat's eligibility to
enter races categorized according to the
WS Offshore special regulations. 

Inclining test 

An inclining test is performed on a boat in lightship measurement trim while floating in calm water and not affected on any side by lying to a mooring, and with no one aboard.  


Alternatively to the procedure defined above and particularly on boats that would require heavier weights to be suspended, a boat’s boom may be used to suspend weights as follows:  








For boats with a canting keel, an inclining test is performed with the keel on centerline. After the keel is fullycanted the resulting heel is recorded so that the effect of the canting keel on the boat's stability can be calculated. A complete explanation of stability curve and
inclining test results can be found in the
Stability and Hydrostatics Datasheet Explanation. 
