Question 1

When preparing a cargo loading plan for a bulk carrier, what is generally considered good practice regarding the percentage of permissible Shear Force (SF) and Bending Moment (BM) used at any stage of loading?

Accepted Answer

Although the class limit allows up to 100%, good practice is to keep SF/BM below around 90% at any stage of loading to allow a margin for deviations from the plan While the ship's loading manual and onboard loading computer may permit shear force and bending moment values up to 100% of the permissible limits, prudent practice is to plan loading sequences that keep these values below around 90% at any stage. This provides a margin to absorb minor deviations from the plan (e.g. delays between holds, ballast operation timing, or tide-related changes) without exceeding structural limits.

Question 2

The yacht is loading additional stores and fuel before a long passage, raising the displacement significantly. What effect does this have on stability that you, as OOW, should be aware of?

Accepted Answer

Increased displacement generally raises the centre of gravity if weight is added high up, and free surface effects in partially-filled tanks can reduce the effective metacentric height (GM) Adding weight changes the vessel's centre of gravity depending on where it is stowed, and partially-filled tanks create free surface effects that reduce GM. OOWs should understand these basic stability principles even on smaller vessels without a dedicated loading computer.

Question 3

During a survey, watertight door seals in a transverse bulkhead below the waterline are found to be perished and not closing properly. As Master, what is the significance of this for the vessel's damage stability?

Accepted Answer

Significant — a failed watertight closure compromises the subdivision the vessel's damage stability calculations rely on, potentially allowing progressive flooding between compartments in the event of damage Damage stability calculations assume watertight subdivision functions as designed. A bulkhead door that cannot seal properly defeats that subdivision, allowing flooding to spread beyond the single compartment the design assumed — this must be rectified before further operation.