oetzi
24-08-2007, 17:04
I got interested in Hammocks for using them in the woods next winter. Makes a bit of a difference from selling them to customers who wouldnt dream of doing so.
So I thought I post some informations I gathered years ago to make live easier in the shop when Hammocks are concerned.
My customers always think, when setting one up, that they can get away with the thinnest, cheapest, most fragile rope lying around. Not realising that this might be a bit dangerous, because the load on each end of a Hammock can far exceed the weight of the user.
This is the case when the Hammock is not set up in the traditional curved way but stretched tight to achieve a flat position for the user.
Digging a bit into long lost knowledge from school, I came up with this (, no scanner):
http://i13.photobucket.com/albums/a273/Supercorsa/Bushcraft/Image00002-1.jpg
http://i13.photobucket.com/albums/a273/Supercorsa/Bushcraft/Image00001-1.jpg
Usually, its not possible to pitch a hammock and use it completely flat. The material will always sag a bit, so the angle will be greater than 10°.
But, as can be seen from the pics, the loads depend on this pitching-angle and may vary a bit from the users weight. Also one has to take into account, that a simple knot or a tight radius will reduce the loadbearing quality of any rope by 30-50%.
For me, after 21 years working retail, there has also to be considered what I call the "DF-quotient", meaning how much of a dumb F**k the customer might be. Sounds harsh, but if something fails I am the one to be blamed, so I like to err on the cautious side.
An example:
Mayself and some equipment amount to ca 100kg. So the load on each rope can be easily 200kg.
A standard static rope (called "Reepschnur") with a diameter of 5mm holds a STATIC!!!!!! load of ca 5,8kN.
So for myself I would be on the safe side with this and if I were a weightweenie would even consider 4mm with 4,1KN.
The customers get a recommendation of 6mm (9,7KN) or better 7-8mm (12,8-14,8KN).
Long term use/abuse and substandard setup have to be considered and who knows how many children might try to climb into the Hammock and jump around etc?
The good thing on the pics above is, that everyone can do as he likes, but with solid neutral information as a Base.
So I thought I post some informations I gathered years ago to make live easier in the shop when Hammocks are concerned.
My customers always think, when setting one up, that they can get away with the thinnest, cheapest, most fragile rope lying around. Not realising that this might be a bit dangerous, because the load on each end of a Hammock can far exceed the weight of the user.
This is the case when the Hammock is not set up in the traditional curved way but stretched tight to achieve a flat position for the user.
Digging a bit into long lost knowledge from school, I came up with this (, no scanner):
http://i13.photobucket.com/albums/a273/Supercorsa/Bushcraft/Image00002-1.jpg
http://i13.photobucket.com/albums/a273/Supercorsa/Bushcraft/Image00001-1.jpg
Usually, its not possible to pitch a hammock and use it completely flat. The material will always sag a bit, so the angle will be greater than 10°.
But, as can be seen from the pics, the loads depend on this pitching-angle and may vary a bit from the users weight. Also one has to take into account, that a simple knot or a tight radius will reduce the loadbearing quality of any rope by 30-50%.
For me, after 21 years working retail, there has also to be considered what I call the "DF-quotient", meaning how much of a dumb F**k the customer might be. Sounds harsh, but if something fails I am the one to be blamed, so I like to err on the cautious side.
An example:
Mayself and some equipment amount to ca 100kg. So the load on each rope can be easily 200kg.
A standard static rope (called "Reepschnur") with a diameter of 5mm holds a STATIC!!!!!! load of ca 5,8kN.
So for myself I would be on the safe side with this and if I were a weightweenie would even consider 4mm with 4,1KN.
The customers get a recommendation of 6mm (9,7KN) or better 7-8mm (12,8-14,8KN).
Long term use/abuse and substandard setup have to be considered and who knows how many children might try to climb into the Hammock and jump around etc?
The good thing on the pics above is, that everyone can do as he likes, but with solid neutral information as a Base.