Bigger and Heavier Topsides Load out case study

Incident occurred at MMHE Yard while loading the 18,000MT topsides for ExxonMobil Tapis R Platform
Skidded/SPMT loadouts are done longitudinally, However in some cases transverse loadouts are carried out
Challenges
Skidded/SPMT loadouts are generally done in steps and are calibrated exercises
The Cargo gradually moves from Quay side to the vessel, As the load transfers to the vessel,the vessel sinks & trims
To maintain the vessels even keel & to keep it level with the quayside is done by calibrating the ballast in the tanks at each stage to maintain the vessels position
The longitudinal strength of the vessel too has to be maintained within limits
Another challenge is tidal variations during the loadout ,ballasting sequence has to take into account the tidal levels during the loadout operation
Following Engineering Inputs are important for loadouts
Study of tidal patterns and draft availability
Vessel selection-cargo size, quay side water depth
Loadout Ballast Engineering It provides the patterns of ballast for different stages of loadout as cargo moves from the quay side to vessel in steps
Stability need to be checked and be within limits

The importance of Loadout Procedure, which shall cover the following:
1. Loadout path, Loadout beam strength, the soil, jetty, obstructions, basin size
2. Ballasting calcs, pumping rate, tidal variation, water depth
3. Bollard and mooring
4. Pulling system, skidding friction
5. Height of grillage, deck and bulkhead strength
The engineering behind it
1. Loss of support conditions
2. COG shift when the module lands on the barge