Actually, it’s simple. There was an article in Popular Mechanics on methods of execution a year or 2 ago.
Said something like: It takes 1250 pounds of force to break the neck. The equation for length of drop is based on that number and the executee’s weight, but I don’t remember it. I’ll see if I still have it.
For you Do-It-Your-Selfer’s out there, this is an excerpt from the State of Delware’s hanging procedures manual. Formulas are included.
PREPARATION
The following procedure should be used to make ready for the gallows prior to the execution. This should be done several days prior to the execution by a Certified Hanging Technician.
Determine the Rope Length for the particular executee. Employ the following formula for this determination and in the event of a multiple execution test with the requirements for the lighter executee and the longer drop. After the first execution, the Rope Length should be shortened for the next execution. Since the test was for the lighter executee, the trap door may be considered to function with the greater weight of the second executee.
Rope Length = (S - C) + Drop Distance
Where: S = Scaffold Crossbeam Height from Scaffold Floor
C = Executee’s Chin Height
Drop Distance = the distance the executee is
dropped
Rope Length = distance of the executee’s drop + the
distance of his chin from the
scaffold crossbeam
Note: All measurements are in inches.
-
Measure the executee’s chin height from the floor and
weigh him. -
Measure the scaffold crossbeam height from the floor of
the scaffold. -
Subtract the Chin Height from the Scaffold Crossbeam
Height and add the Drop Distance from the Drop Distance
Table to obtain the Rope Length. -
Mark the rope at the rope length and cut it seven (7)
feet longer. If fastener for rope is not at crossbeam
but at another location, add this distance to the
crossbeam height plus any additional amount needed for
fastening. -
Boil the rope for one (1) hour and stretch the rope
while drying to eliminate all spring, stiffness or
tendency to coil. Dry thoroughly. -
Either tie Conventional Hangman’s Knot as per included
instructions or utilize a Mechanical Hangman’s Knot and
fasten with U-clamp. Lubricate Hangman’s Knot with
proper lubricant. -
Install the Rope with the Hangman’s Noose to the
scaffold crossbeam and cut off remaining rope. The rope
should be stretched tight prior to cutting and only the
Rope Length should hang below the scaffold crossbeam. -
Oil, check and verify that all mechanical parts of the
Gallows (i.e. the hinges on the trap door and the
release mechanism) are functioning properly. -
Fill two (2) sandbags with the equivalent weight of the
executee (half in each bag) and fasten the bags together
at the tops. Open the Noose and slip it over one of the
bags and tighten it at the point where the bags are
fastened together. You are now ready to test the
gallows. -
Close the trap door and reset the trip mechanism. Stand
on the door to make sure it is secure. Place the
sandbags on the door and loop the rope in such a fashion
as to prevent any crimping or catching. Test the
gallows repeatedly (at least twelve [12] times) to
insure proper mechanical operation of the trap door and
that the rope is secure and will not break. -
You are now prepared for the execution.
EXECUTION PROCEDURE
Note: The following procedure should be completed by a
Certified Hanging Technician.
-
Install the Noose Sleeve and, if using a Mechanical
Hangman’s Knot, install the cover for the Knot. -
Install the Body Restraint around the Executee’s waist
and tightly bind his wrists to the restraint. (His arms
may be restrained either in the front or the back.) If
necessary, utilize the Collapse Frame. -
Bring the Executee to the Execution location and up the
stairs to the scaffold. Remove the Collapse Frame, if
utilized. -
Place Executee on the trap door and conduct the legal
formalities. -
Bind the Executee’s legs with the Leg Restraint. Place
the Hood over the Executee’s head, if used. Place the
Hangman’s Noose over the Executee’s head and tighten
snugly around his neck. Place the Hangman’s Knot
directly behind the Executee’s left ear. -
All Hanging Technicians shall leave the scaffold and the
Executioner, on order from the Warden, shall release the
trap door. -
The Trap door shall open and the Executee shall drop. On
order from the Warden some eight minutes after the
release mechanism was thrown, the attending doctor shall
examine the Executee for heart death. -
After the pronouncement of death, the Hanging Technicians shall, while supporting the Executee, loosen and remove the Noose and Hood and set the Executee on the floor. Thereupon, the Hanging Technicians shall remove the Leg and Body Restraints. The Executee shall be placed in a body bag for removal.
what exactly is the “mechanical hangman’s knot”? I’m only familiar with the conventional.
If done correctly hanging is actually a fairly humane way to put someone down. The rope needs to be positioned correctly and the body needs to be dropped from a certain height to ensure that the neck breaks cleanly.
Marc