Hello, sorry for my ugly and poor and partially Google translated english.
I don't have a car, but equally i was curious to search for some knots useful to towing a vehicle.
I'm italian,and searching with Google using my language,i found this document,
which is a part of a series of tutorials of fire department of the italian ministry of the Interior:
https://docs.google.com/viewer?a=v&q=cache:3mUZ-3n-CBYJ:www.vvfnapoli.it/document/DISPENSE/Dispensa%2520Funi%2520Nodi.pdf+nodo+da+traino&hl=it&gl=it&pid=bl&srcid=ADGEESjoGxZD_HZQinECP1ho62mESDUlSFaoSfcSOZp17CKFA30-IgWT4F_uBb6EMHudWWafSvwySIpZfsJNXybWS_SBTn7QXNsjqtiN9CccXNI1wYYw0rSybXrmdQH67oAKfsVOfjj0&sig=AHIEtbRRu90S_V3EFOJVRoXopgjBg-H4Vwon page 71 there is a loop called"Nodo da Traino Semplice"(Knot for Tow Simple).
At first it seemed to me a Carrick Loop,but it is not:is a loop version of ABOK #1443,
a bend marked dangerous with skull and bones symbol in the Ashley Book of Knots.
At first I thought a crass error in tying illustration,but after i found this page at the italian fire department site:
http://www.vigilfuoco.it/aspx/Page.aspx?IdPage=4136&index=1&IdImg=4519is the same knot(a mirror version of the former).
The old style drawing of this second picture suggests to me that this knot has been used for decades and more
(and probably not only by italian fire department).
Assuming however that fire departments today normally use other tools for towing a vehicle,
like rigid bars or steel cables,i believe,and assuming that anyhow fire departments know what they do,
I ask you members of this forum an estimation in respect of the use of this knot.
Maybe being not a bend but a loop, when it is under strain the forces acting in a manner that the knot will not slip?
(anyhow shaking and tearing the loop and the standing part with the only strength of my arms the knot sometimes is slipped)
A stopper/backup knot solves many problems,but it would be better to use a true Full Carrick Loop,
or some better loop or hitch for this purpose?
Can happen that someone is in trouble using this knot without a stopper/backup knot after viewing these files?
On page 55 the title of the section on knots of fire department tutorial says"nodi con corde in canapa"(knots with hemp ropes),
maybe this loop results more"secure" tied in a old twisted strands hemp rope? This type of rope is still used by fire departments?
Thanks you all for your possible attention about these questions
Regards to you all
Luca
P.S.
Sorry,but actually i'm on a O.S. called "Puppy Linux" because of problems with my graphics card and I can' t post active links as i did when I used windows