Slide your tandems, manage tail-swing, and back into the tightest dock without a spotter.

Use the Truck Triangle to judge whether an obstacle will be hit during a turn.
The Truck Triangle is a simple way to predict what your trailer will hit during a turn. Imagine a straight line drawn from your steer tire to the trailer tandems. Any obstacle that stays outside that line is safe. Anything that crosses the line — or ends up inside the triangle between your steer axle and tandems — will be hit.
Turning toward an obstacle can pull it into your triangle. Turning away can move it out. The technique does not work well for turns sharper than 90° because the tandems start moving backward and the trailer is more likely to jackknife. Use it as a quick visual reference, not a substitute for proper turning technique and mirror checks.
Technique courtesy of Chris Icenhower and James Boyce.
Backing into a dock — slow, deliberate, and always G.O.A.L.
Permission granted by Junior Honduras YouTube Channel.