Schluf describes a narrow point in a cave or in a cave system, which a person can usually only pass by crawling on the ground. This locomotion is referred to as "slipping" or "sleeping" (see also crawling ).
Many horizontal gaps or narrow tubes form gaps. A silt places high physical demands on cave visitors, and in the case of claustrophobia also psychological demands. Sometimes there is a risk of getting stuck.
In some holes you can crawl on all fours. If the silt gets lower, you have to dig. Sometimes both arms have to be stretched forward and sometimes the helmet has to be removed. If the silt becomes too narrow horizontally, it can be conquered by just stretching one arm forward and pressing the other arm as close as possible to the body. One of the largest problem areas in the human body, the shoulders, becomes smaller. Even narrower gaps are overcome by pushing yourself a few centimeters forward while breathing out and then getting stuck again when breathing in. There is a risk of not getting enough air.
The Befahrung of vertical Schlufen usually represents the highest level of impact on man and climbing equipment. A silt, the horizontal would be crawling easily navigated is vertically usually impassable. A silt that is impassable is called an impassable silt .
The difficulty of bottlenecks can be divided into 7 categories:
- Bend over, move on your feet
- Crawling point, moving on hands and knees
- Creeping distance, movement on elbows, stomach and toes, hardly any rock contact with the back
- tight, sliding on the stomach, rock contact with parts of the cross-section of the body
- very tight, the entire cross-section of the body is in contact with the rock, helmet often has to be removed, breathing technique becomes important
- extremely tight, only possible with full exhalation and with a lot of experience
- extremely tight, intensive concentration and psychological preparation necessary
- Lukas Plan, Eckart Herrmann and Dieter Sulzbacher: Speläo-Merkblätter des Verband Österreichischer Höhlenforscher, “A26a Schliefen” . 2007.