Chemical Tankers / Day 4 / Day 4 Topic 2 Cargo Quantification

Cargo Calculations

Consider also whether ship or shore has stopped the cargo – ie: if you stopped short,

On discovering a shortage of cargo, this must be discussed, re-gauging done and a request to resume loading to take the difference (It is always going to be better to take the cargo – and earn freight - than to simply issue a protest)

Ship’s figures and Surveyor’s figures may be slightly different – always work from ship’s figures

Cargo Calculations

A Letter of Short Loading is also issued for a cancelled cargo (as is a Notice of Readiness). In this case, it is termed a “Deadfreight Letter”. On occassions a different cargo is substituted and the Ship Operator will then issue specific instructions on whether a claim is to be issued or not

In the case of a deadfreight cargo, claim for what could have been lifted in practice

Cargo Calculations

Example 11:

Nomination: 1000 mt 5% MOLOO

Range: 950 - 1050 mt

Tender: 1050 mt Agreed as Shore Stop

Issue Short Loading for above

Cargo Calculations

Example 12:

Nomination: 1000 mt 5% MOLCO

Range: 950 - 1050 mt

Tender: 1050 mt Agreed as Shore Stop

Ship’s Load Figure: 997.883 mt

Within Option

Cargo Calculations

Example 13:

Nomination: 1000 mt 5% MOLOO Range: 950 - 1050 mt

Tender: 1050 mt Agreed as Shore Stop

Cargo Calculations

Example 14:

Nomination: 1000 mt 5% LOO

Range: 950 - 1000 mt

Tender: 1000 mt - Agreed as Shore Stop

Shore declare rail cars unavailable – cargo cancelled

Notify Ship Operator immediately, issue Notice of Readiness and Short Loading, both for 1000 mt

Cargo Calculations

Loading Restrictions and Limitations:

Structural Limitations:

Data Sources: Appendix to Class

P&A Manual

Commonly in terms of Density, Pressure or Temperature restrictions and usually indicated as “Filling Height” limitations

Cargo Calculations

A “Maximum Permissible Density” does not mean that cargo of a higher density cannot be loaded, but the amount of cargo must not exceed the equivalent weight calculated using that maximum density

However, there may be barred filling range heights to avoid “sloshing damage” in a slack tank

The problem is usually only encountered with Acids, Chlorinated Solvents and Caustic Soda Solution, ie: higher density cargoes

Information may be available in graph or table form, although the calculation is also easy to do

Cargo Calculations

Example 15:

Maximum Permissible Density: 1.05 Capacity of Nominated Tank: 673.4 m3 at 98%

Max weight of cargo to load: 707.1 mt

Cargo Calculations

Minimum Filling Heights:

“Sloshing Levels” - designed to prevent damage to tank structure, heating coils, ladders, etc

With cylindrical (deck) tanks, both maximum and minimum filling levels will usually be found