Commercial Marine / Towing / Technical Guide Towing Pennants in Tug Operations: The Sacrificial Link That Protects Your Mainline On a working tug, the pennant is one of the least expensive components in the towing assembly — yet it has a major influence on mainline life, connection speed and the reliability of the towing system under load. This guide is written for tug masters, marine superintendents and harbour towage operators: what the pennant is there to do, how the two strength philosophies differ between ship assist and ocean towing, and what two recent UK tug incidents taught the whole industry about inspection and retirement.