METHOD TO CONTROL SHIP STABILITY Russian patent published in 2010 - IPC B63B39/14 

FIELD: transport.

SUBSTANCE: invention relates to control over ship stability during heaving. Method comprises additional measurement of the ship bow and stern draft, relative bearing and speed in irregular heaving, wind speed, ship location coordinates and distance to nearest shelter port. In estimating ship stability at current load, water layer depth in deck shaft is measured for ship straight position to define the arm of heeling moment caused by water running onto deck. Measured angle at which bulwark edge enters the water, heel angle, bow and stern drafts are used to calculate ship displacement and current heel moment. The latter magnitude is represented in the form of graphic dependence on heel angle to be compared with marginal critical diagram of ship stability on wave top calculated with due allowance for normalised parametres of heaving. Note here that stability estimation is performed by criterion based on calculation of actual transverse metacentric height of ship center of gravity for current diagram of stability on wave top the magnitude of which may not exceed critical transverse metacentric height of ship center of gravity for marginal diagram.

EFFECT: higher validity of stability estimation.

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