🔍 Key Concepts

• Lever arm and moments created by hook load and setback weight relative to the vessel’s center of flotation or reference point • Using the lightweight changes and KG/LCG data from the Operating Manual to stay within allowable stability limits • Relationship between total vertical load (hook + setback) and the maximum permitted combined moment in the manual’s loading tables/curves

💭 Think About

• How does the distance of the rotary from the transom and centerline affect the moment created by the hook load and the setback weight? • What combined hook + setback condition does the Operating Manual show as the maximum allowable before exceeding trim or stability limits? • If you convert the maximum permitted moment from the manual into a total allowable vertical load, what part of that is already ‘used up’ by the 300‑kip hook load, and what remains for setback?

✅ Before You Answer

• Confirm the reference point (transom, centerline, or another datum) used for moments in the Operating Manual tables or diagrams. • Verify units: ensure all loads are in kips and all distances are in feet when computing moments (kip‑ft). • Check that the selected option gives a setback which, when combined with the 300‑kip hook load at the given locations, does not exceed the manual’s maximum allowable moment or stability limits.