A semisubmersible 300 feet long and an LCF of 0 (amidships) is in transit with hulls awash and an MT1" of 87.67 foot-tons. Work on the BOP (weight 263 long tons) requires that it be moved aft 12 feet. What is the resulting trim change?
A. 1.5 feet
B. 3.0 feet
C. 6.0 feet
D. 7.3 feet
A. 1.5 feet
B. 3.0 feet
C. 6.0 feet
D. 7.3 feet
Just like a ship!
ReplyDeleteChange of trim = Trimming Moment / MT1
In this case the Trimming Moment = Distance from LCG x Weight = 12 feet x 263 Tons = 3,156 Foot Tons
Change of trim = Trimming Moment / MT1 = 3,156 Foot-Tons / 87.67 Foot-Tons/inch = 35.99 nches or 3 feet.
The best answer is B.
While the terminology sounds strange to Merchant Mariners, the math is no different than on ships. Distance and Weight are still Distance and Weight.
To answer this you also need to know MT1" = Trimming Moment / one inch of trim
ReplyDeleteDouble Rogers
ReplyDelete263 LT * 12 Ft/87.67 FtT MTI=35.99" or 3 ft