Question 4612 Deck General

The correct answer is C) KG. On a semisubmersible drilling unit, decreasing riser tension reduces the vertical center of gravity (KG) of the unit. This is because as riser tension decreases, the riser becomes more relaxed and contributes less to the overall weight distribution, causing the center of gravity to shift downward. The other options are incorrect because: A) GM (metacentric height) is not directly affected by changes in riser tension. B) Free surface moments are related to the free surface effect, which is not directly impacted by riser tension. D) KM (vertical center of buoyancy) is also not directly affected by changes in riser tension.