The COASTAL DRILLER, while in an ocean...

Question 1 of 2707066636ee728f7522a1c517747

The COASTAL DRILLER, while in an ocean transit, experiences a single amplitude roll of 8 degrees. What is the minimum period of motion which does not exceed the design limits of the legs?

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Question 1 of 27070

The COASTAL DRILLER, while in an ocean transit, experiences a single amplitude roll of 8 degrees. What is the minimum period of motion which does not exceed the design limits of the legs?

🔍 Key Concepts

• Relationship between roll amplitude (in degrees) and allowable roll period for self-elevating/mobile offshore drilling units (MODUs) • How a single-amplitude roll is interpreted in stability/design limit tables (often tied to a limiting period vs. angle curve) • Understanding that a longer roll period means a slower, more gentle motion, and a shorter period means quicker, more severe motion for the same angle

💭 Think About

• Look at how the design limits are usually presented: for a fixed roll amplitude (8°), would the allowed period be closer to the very short, very quick motions or toward the slower, more gentle motions? • Think about which periods (4, 6, 8, 10 seconds) would produce the most stress on the legs at the same angle—faster oscillations or slower ones? • Ask yourself: If the unit is within design limits at 8° single-amplitude, what is the shortest (minimum) period that still stays on the safe side of the leg-load curve?

✅ Before You Answer

• Carefully distinguish amplitude (angle) from period (seconds)—they are not the same thing. • Recall that a shorter period means more rapid cycles, potentially higher dynamic loads at the same angle. • Visualize or recall the typical design limit curve for jack-up legs: for 8° single-amplitude, identify which side of the period range (short or long) would generally remain within limits.