Hitch Configurations, Capacities, and Basic Knots
Hitch types and how capacity changes
A vertical hitch uses one leg straight up and gives full rated capacity. A choker hitch wraps the sling around the load and chokes it; it typically reduces capacity to about 75-80 percent of vertical. A basket hitch cradles the load and can roughly double capacity when both legs are vertical. A bridle hitch uses two or more legs at an angle to a common point.
The sling angle effect
As the angle between the sling leg and horizontal decreases, tension in each leg increases. At 60 degrees, each leg carries about 1.15 times half the load; at 45 degrees, about 1.41 times; at 30 degrees, about 2 times. Never rig below 30 degrees from horizontal without engineering approval. Memorize the load factor concept: tension = (load / number of legs) / sin(angle).
Basic knots and terminations
Know the bowline (creates a fixed loop that will not slip or jam), the clove hitch (quick attachment to a post or rail), and the timber hitch (used to drag or lift logs). Knots reduce rope strength - a bowline can cut capacity by 30-40 percent. For lifting, prefer certified slings and hardware over knots.
Traps
The exam loves to test whether a choker reduces capacity, whether basket doubles capacity only if legs are vertical, and whether a sling angle below 30 degrees is acceptable. Also watch for questions about D/d ratio (bend radius) reducing capacity.
Rule of thumb
For quick field math, remember 60° = 1.15, 45° = 1.41, 30° = 2.0 tension multipliers.