Trebuchet Rules Clarification

This is a clarification of how trebuchets are measured for classification in the different weight divisions: lightweight, middleweight, and heavyweight. See the official rules for specifications.

The height of the trebuchet is the difference between the top and bottom.

The top is the highest point reached by the arm (including the finger) or the counterweight (CW) during firing. The bottom is the lowest point of the arm or counterweight during firing.

For a King Arthur trebuchet two measurements are made when the trebuchet is at rest; the highest point of the finger and the lowest point of the counterweight. Two measurements are made when the treb is loaded; the highest point of the counterweight and the lowest point of the finger. See figures 1 and 2.

All four measurements are made from a convenient fixed level; the ground is a good level or the lowest point of the trebuchet.

The four measurements are:

1. Highest point of finger at rest
2. Lowest point of CW at rest
3. Lowest point of finger when loaded
4. Highest point of CW when loaded

The top is the highest of all four points and the bottom is the lowest of all four points. So the height of the trebuchet is simply the distance between the highest top and the lowest bottom.

See figures 3 and 4 for a floating point trebuchet measurements.

If you have any questions please contact the event organizer, Dave Jordan.