Advanced Calculations

Calculations on how much cargo securing is needed for a cargo unit are done by using advanced calculation methods.

When calculating the requirements for securing, you can take the transverse and longitudinal forces independently. This allows you to calculate the lashing requirements for athwartships and longships movements and secure the cargo according to these needs.

The formulas, both simplified and advanced examples, provide a securing requirement in tonnes. The simplified versions are specifically for symmetrical lashing arrangements on closed decks where all of the angles for lashing equipment will be the same.

In addition to the sliding calculation, there must also be a consideration of tipping in longitudinal and transverse directions. In the main, longitudinal tipping is highly unlikely, given the shape of the container. Transverse tipping, however, must be carefully considered and the requirements fully calculated to ensure the cargo does not tip during transport.

An example of an advanced calculation is shown below.

To make these calculations may be time-consuming if it is done by hand, so preferably calculations for the most common types of cargo/cargo units should have been done and the result presented in the vessel CSM in a visual form that is easy to understand, for example in a table.

For a few rare cargo types that shall be loaded onboard, cargo securing calculation may have to be done before the cargo unit is loaded to check if it can be secured properly.