Answer
What is a Loadicator?
A Loadicator (Loading Computer) is a class-approved electronic device (software or hardware system) mandatory under SOLAS Chapter II-1 and MARPOL Annex I/II for tankers and bulk carriers. It simulates and calculates the vessel's stability, buoyancy, and structural integrity for any given condition of cargo, ballast, fuel, and fresh water loading before the actual operations begin.
Stresses Calculated by the Loadicator
The system performs real-time structural and stability computations based on hydrostatic data to evaluate:
Longitudinal Bending Moment (LBM): Evaluates the sagging or hogging stresses acting along the ship's length by comparing local buoyancy forces against structural weight distribution.
Vertical Shear Forces (SF): Measures the upward and downward tearing forces acting at the transverse bulkheads or structural transitions.
Torsional Moments: Calculated specifically for container vessels, multi-hatch bulkers, or chemical carriers with asymmetrical tank configurations, where uneven cross-loading exerts twisting stresses on the hull girder.
Intact & Damage Stability Parameters: Calculates the Metacentric Height (GM), righting lever (GZ) curves, draft, trim, and angle of heel to ensure compliance with the IMO Code on Intact Stability.
Where are Stress Sensors Fitted?
Modern hulls (especially large Capesize bulk carriers, VLCCs, and container vessels) are equipped with active Hull Stress Monitoring Systems (HSMS) linked directly to the Loadicator.
Longitudinal Deck Girders: Long-gauge strain gauges (fiber-optic or electrical resistance type) are welded or bolted to the main deck stringer plates on both port and starboard sides, typically near the midship region (0.4L to 0.6L from aft) where bending moments peak.
Transverse Bulkheads / Cargo Hold Boundaries: Strain sensors are located at the lower boundaries of deep bulkheads or cross-deck strips to measure localized shear forces.
Neutral Axis & Bow Area: Accelerometers and strain sensors are placed in the forward 0.25L region (fo'c'sle deck or forward deep tanks) to monitor dynamic forces like bow slamming, pounding, and whipping in heavy seas.