An Umpire will only warn a crew for its steering during a race if it is about to:
2-5-3a: Interfere with another crew,
2-5-3b: Foul another crew,
2-5-3c: Gain any unfair advantage by leaving its proper course (e.g. cutting a corner),
2-5-3d: Collide with a temporary obstruction on the course.
NB in bow-coxed boats, the cox cannot see the umpire and may not be able to hear warnings clearly, so the crew member at bow must pass on any warnings.
To warn a crew:
Raise the White Flag vertically,
Name the crew,
Point the flag at arm's length in the direction the crew must move,
When the crew responds, the Umpire drops the White Flag out of sight.
If the crew fails to respond, the whole sequence may be repeated.
Click here or on the "Umpire" to repeat the animations in a new window.