Question 4330 Deck General

The correct answer is B) 50 feet. When the maximum leg penetration of a jackup rig like the COASTAL DRILLER is 75 feet, the water depth value in the Allowable Wind and Wave Charts must be increased by 50 feet. This is because the legs of the rig can extend up to 75 feet below the water surface, and the Allowable Wind and Wave Charts are based on the total water depth, which includes both the surface depth and the leg penetration. By increasing the water depth value by 50 feet, the charts account for the additional leg penetration and provide the appropriate limits for safe operation. The other options are incorrect because 75 feet would be the leg penetration itself, not the required increase in water depth value, and 25 feet or 0 feet would not properly account for the full leg penetration.