University Of Tasmania

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Establishing uncertainty analysis procedures for inaccuracies in operational ship stability

conference contribution
posted on 2023-05-23, 15:02 authored by Hossein EnshaeiHossein Enshaei, Michael WoodwardMichael Woodward, Uge, C, Kianejad, S

The ship stability is essentially assessed for all ships before, after and during the operation. The purpose of assessing ship stability is to ensure the ability of ship to float and return to an upright position if inclined under the action of an external force. Ship stability, as with other critical parameters relating to ship operations, is of paramount importance and should therefore be dealt with accordingly with an appropriate uncertainty analysis. Uncertainty analysis is commonly utilised in a design to establish the uncertainty in result as a function of the input variable. This can in turn be utilised to establish an interval about the result that may be expected to encompass a large fraction of the distribution of values that could reasonably be attributed to the measurement. This paper provides a methodology for calculating a confidence interval for the centre of mass of a ship in operation and ultimately, in any load condition.

The uncertainty for a sample containership was carried out by considering the effect of weights on the centre of gravity of the ship. It appears that variation in height of cargo in containers can change the 𝐾𝐺 by as much as ±0.164m. The uncertainty of weighing appliances could be up to ±250kg for individual container, and sediment in ballast tanks could potentially reduce the centre of gravity of the tank by -0.5m.


Publication title

Proceedings of the 1st International Conference on the Stability and Safety of Ships and Ocean Vehicles




Australian Maritime College


STAB&S 2021

Place of publication

Scotland, UK

Event title

Stability & Safety (STAB&S) 2021: 1st International Conference on the Stability and Safety of Ships and Ocean Vehicles

Event Venue


Date of Event (Start Date)


Date of Event (End Date)


Rights statement

Copyright unknown

Repository Status

  • Restricted

Socio-economic Objectives

International sea freight transport (excl. live animals, food products and liquefied gas)

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