Escort tugs use the combination of yaw angle and azimuthing thrusters to generate the hydrodynamic forces that are used to control a disabled tanker. The yaw angles used in escort operations (35-55 degrees) are considered to be extreme "off-design" conditions in normal naval architecture terms but in the case of an escort tug they are expected operating conditions.
National Research Council of Canada. Institute for Ocean Technology
St. John's, Newfoundland, Canada
Technical Report (National Research Council of Canada. Institute for Ocean Technology), no. TR-2005-03 (2005).