A vessel's KG is determined by __________.
A. dividing the total longitudinal moment summation by displacement
B. dividing the total vertical moment summation by displacement
C. multiplying the MT1 by the longitudinal moments
D. subtracting LCF from LCB
A. dividing the total longitudinal moment summation by displacement
B. dividing the total vertical moment summation by displacement
C. multiplying the MT1 by the longitudinal moments
D. subtracting LCF from LCB
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ReplyDeleteKG is the Vertical Height of G, the Center of Gravity, above the baseline which passes through the bottom of the keel. KG is determined by using a method known a "Weighted Average" which can be Googled for more information. Basically the Weighted Average Method is comprised of:
ReplyDelete1. Determining all the known weights on the vessel including the Light Ship Weight of the vessel itself, cargo and consumables liquid and dry.
2. Determining the distance of each known weight from the baseline or keel upwards to its own center of gravity.
3. Multiplying each weight by its distance to create its Vertical Moment.
4. Adding all Weights and Adding all Vertical Moments.
5. Dividing the Total Vertical Moment by the Total Weight or Displacement = KG
Simple Numerical Example of the Weighted Average Method:
Item: Weight x Distance = Moment
Lt Ship: 10,000 tons x 9.0 meters = 90,000 m-tons
Fuel Oil: 500 tons x 0.5 meters = 250 m-tons
Diesel Oil: 50 tons x 5.0 meters = 250 m-tons
Fresh Water: 100 tons x 8.0 meters = 800 m-tons
Constant: 90 tons x 11.5 meters = 1.035 m-tons
Cargo: 35,000 tons x 8.5 meters = 297,500 m-tons
Ballast: 75 tons x 0.2 meters = 38 m-tons
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TOTAL Weight = 35,815 tons; TOTAL MOMENT = 299873 m-tons
KG = TOTAL MOMENT /TOTAL Weight = m-tons/tons = meters
= 299873 m-tons/35,815 tons = 8.37 meters
DO YOU AGREE OR DISAGREE?