In illustration D024DG below, what is the purpose of item "G"?

Correct Answer: Option B — prevent the knee from shifting when the rudder is put hard over

In barge towing configurations, the 'knee' or 'push knee' provides a contact point for the tug. The specific component identified prevents the knee from shifting laterally when the tug applies rudder, ensuring the tow remains rigid and responsive to the tug's steering inputs during maneuvering in confined waterways.