This is purported (see Stone1 and Clark2) to cause very quick, and almost painless (possibly for a millisecond) death by way of fracture-dislocation of the upper neck vertebrae, which crushes or severs the spinal cord leading to immediate unconsciousness (in a matter of milliseconds). The cause of death is asphyxiation, which occurs whilst comatose. Clark reports estimates that brain death will occur in around 6 minutes and whole body death normally within 10-15 minutes. He also mentions that this time is very variable, with official reports of from 3-25 minutes for total death to have occurred. Some slight movements of the limbs and body may occasionally occur but are almost certainly due to spinal reflexes.
Drop hanging is said to be relatively painless providing the spinal cord is successfully crushed or severed. However, due to the logistics required for this method to be effective it is a lot less popular than suspension hanging as a form of suicide.
Considerations for drop hanging include:
Strong rope that does not stretch e.g. hemp or manila, that can take around 1,000 pounds of pressure, and long enough to tie to something solid and achieve the required drop (see below). Clark reports that in countries which still perform hanging, an eyelet (a metal loop) in the rope is used in place of a knot to make it more free running, and that this causes a quicker death (although would not seem to be essential). He reports that a 13 foot length of ¾" (19mm) diameter hemp rope is often used. Stone recommends 1" (25mm).
Knot positioning. Whilst the type of knot is not essential as long as it does not come loose, it is important that the knot (or eyelet if used) is positioned below the jaw. It may be worth testing what happens with the knot when pulled up to ensure that it finishes as directly below the chin as possible. That might mean its initial position (which should not be pulled tight) is slightly to the side so it becomes central when pulled up. The aim is for the knot to assist in throwing the head back, thereby helping to crush the spinal cord. Clark states that the hangman's knot used in America was aimed to assist in this, although in Britain and its colonies a much simpler basic noose was/is used. For information on knots see http://www.realknots.com/knots/noose.htm.
Attachment of the other end of the rope. Must be to something solid that will not break or move as a result of the pressure of the body dropping. The rope must be knotted securely so the knot does not slip.
Drop. Ideally this needs to be straight down. Running jumps can alter the positioning of the knot and then not achieve severing the spinal cord. Death is still likely, but by strangulation which may be more painful. The length of the required drop varies according to weight. A table of drops for hangmen to use was issued by the British Home Office in 1892 and subsequently revised in 1913. Clark reports that the 1913 table is still used in Singapore and probably Malaysia and may have been adopted by other countries which use the British method, e.g. Australia, Canada, the Caribbean nations and Egypt. This table is reproduced below (the American Military manual specifies broadly similar drops):
The weight of the prisoner is the weight recorded when they were weighed, clothed, the day before execution.
Weight of prisoner (lbs)
Drop in feet & inches
118 & under
200 & over
Clark states that from around 1939 it became customary to add a further nine inches to the drop shown in the above table.
Note that there are references in literature to a formula to calculate drop height of:
Drop in feet =
Your weight in pounds
However, this formula (designed to give a force of 1,260 lbs when the rope fully extends with the body) was revised by the Home Office to avoid decapitation and near decapitation. The Home Office aimed for a force of 1,100, which is effectively the table above plus nine inches. Extending the length of the drop from this may not be a good idea (especially for whoever has to pick up the pieces and identify the body... ).
Further information about drop hanging, together with what some readers might find shocking pictures of types of gallows and hangings, can be found on http://www.capitalpunishmentuk.org/hanging2.html#long.
It should be noted that whilst this method is reported to produce instant loss of consciousness if done correctly, the elements to ensure this happens are not straightforward.
Geo Stone, Suicide and Attempted Suicide, 1999.
Richard Clark. Capital Punishment UK www.capitalpunishmentuk.org 1995.