Tank Top Strength and Cargo Distribution Limits

Permissible tank top loading is the constraint that governs how a dense solid bulk cargo may be distributed, and it is expressed as a uniform distributed load in tonnes per square metre in the ship’s approved loading manual. The load the structure sees is the product of the cargo bulk density and the stow height, so a heavy cargo reaches the limit at a low pile while a light one may never reach it at all.

The full article will cover the derivation of the permissible figure, the difference between the uniform distributed load case and a local pile or cone, and how the loading instrument is used to confirm that a proposed distribution stays within both the local limit and the hull girder shear force and bending moment envelopes.

It will also cover the pour sequence, since the governing case is often an intermediate condition rather than the completed loading. Alternate hold loading, restricted on many bulk carriers under SOLAS chapter XII, and the interaction with the ship’s loading booklet and the terminal’s loading plan will be treated alongside.