They have filters on both the transfer and the engines but part of the transfer sampling is visual inspection.
You know, we were required to keep our samples and send them in for analysis and storage, if they did any...then they have them.
As far as the ISO Standard, you can meet it but fail to take samples correctly, if they were sampling correctly, they would have detected this.
We run each sample through a battery of tests, one of them is a disc filter, if you run the fuel through the disc you do a visual inspection of the disc, we also did a flow test on the filter to ensure there wasn’t invisible damage caused by the fuel.
Honestly, if they did it...this wouldn’t have happened.
The transfer tests exceed the standard for 50% of the samples, it is statistics. Any random sample can pass, you have to do the correct number of samples depending on how much is being transferred based on the flow rate..
Our sampling was anywhere from every 2-10minutes.
I said sabotage, because I know you could supply filters to these ships with compromised fuel filters, that would do it...even if the fuel met spec.
If something like this happens, a proper investigation is to retrieve the fuel filters for analysis.