Q.During topping up on tankers, How to calculate notice time to the loading master for stopping the cargo?

The first thing that we need to know is if the line content of the shore line will be blown into the ship's tanks or not.

This information is part of ship shore operational agreement with the loading master before the commencement of the loading operation.

Now let us say that in the ship shore operational agreement it is agreed that shore line will be blown into the ship's tanks. In this case, we need to know the volume of the shore line. Loading master will provide this information. Let us say the loading master has given 20 m3 as the shore line content.

We have to load 2312 m3 of cargo in each of the two final topping up tanks (Say in 4P & 4S cargo tanks). That makes total cargo of 4624 m3 in these two tanks.

Minus the shore line content, which means that we need to stop the cargo when total content in these two topping up tanks is 4604 m3.

We also need to specify the final topping up rate in the ship shore operation agreement. Let us say it has been agreed with the loading master that final topping up rate will be 200 m3/hr.

Now we can have an excel sheet where we have calculated the total volumes in these two tanks at the time of notices we need to give to the loading master.

The excel sheet could look something like this.

It is a good idea to have this sheet prepared and attached to the cargo loading plan so that we are not stuck with the calculation while topping up.