LOC Subsea Dropped Object Study

Kola Obayomi LOC

LOC analysis of subsea dropped objects and the interpretation of the DNV code. A model shows the various deviation angles a dropped object may follow subsea, depending on object weight/shape, water depth and other factors. The new DNV code includes “a recommendation that the safe distance should be calculated considering the maximum possible dispersion angle for each type of object falling through the water. If detailed assessment is not made, the safe distance can normally be taken as the larger of 50m or that determined from a dispersion angle of 20 degrees o to the vertical”. At the DROPS Forum Kola presented a series of probability examples and some animated examples clearly showing the different trajectories of different shaped objects. Kola concluded that any assessment should follow the ALARP principle.