What is the principal danger in attempting to swing a barge on a hawser in order to slow the barge's speed?

Correct Answer: Option A — The barge may pass under the hawser and capsize the tug.

Swinging a large barge across a hawser to kill headway creates massive transverse forces. The barge's momentum can carry it sideways faster than the tug can maneuver, causing the hawser to sweep low across the water, pass under the tug, and capsize it.