Max weight/line stress

[Just Jeff]

Chuck would roundhouse kick the clouds and make it rain, so you wouldn't need those 2L bottles. And a tattoo of Chuck's boot on your forehead is MUCH worse than a MagLite one.

Can't wait to see the test results. One thing I can think of - the scales will necessarily extend when you weight the hammock, so you might not be able to get good readings for heavy weights and low angles. Still, the data will be useful.

[blackbishop351]

Can't wait to see the test results. One thing I can think of - the scales will necessarily extend when you weight the hammock, so you might not be able to get good readings for heavy weights and low angles. Still, the data will be useful.

I'd thought about that, too. One way around it - albeit much more difficult logistically - would be to use a fine-calibrated stress meter instead of a scale. They use a sold piece of metal, which doesn't noticeably flex under load, and measure its perturbation from equilibrium via current or magnetic field fluctuations. They're a lot more accurate than a scale for measuring forces, but also harder to find and more expensive. On the other hand, HE can probably get his hands on one, being an engineer

[Coffee]

I'd thought about that, too. One way around it - albeit much more difficult logistically - would be to use a fine-calibrated stress meter instead of a scale. They use a sold piece of metal, which doesn't noticeably flex under load, and measure its perturbation from equilibrium via current or magnetic field fluctuations. They're a lot more accurate than a scale for measuring forces, but also harder to find and more expensive. On the other hand, HE can probably get his hands on one, being an engineer

No but I can get ahold of wind gauges, capacitive and piezo strain gauges and the controls and post processing needed. Strain on these would not be as useful I think. All of us are using some sort of static line. Yeah there is some stretch to them and the straps, but it is definitly a non-linear system.

I still say a simple fish or pack scale will work. Two would be perfect to measure each end. That would take placement in the hammock out of the equation.

[Bird Dog]

I'm not a big fan of Chuck as far as martial arts go, but I think I'd rather have him than a maglite in a survival situation. Why? Because if nothing else I could make him carry my gear if I broke a leg or something!

You could use your maglite as a support pole on your hammock to load the rest of your gear in and use it like a sled. Still rather have the maglite. BD

[1stoffoot]

guys,

been looking for the diagram for hammock set up with rope stress info on it, i`ve seen it on here before but cant find it, please help.

K

[warbonnetguy]

I'd thought about that, too. One way around it - albeit much more difficult logistically - would be to use a fine-calibrated stress meter instead of a scale. They use a sold piece of metal, which doesn't noticeably flex under load, and measure its perturbation from equilibrium via current or magnetic field fluctuations. They're a lot more accurate than a scale for measuring forces, but also harder to find and more expensive. On the other hand, HE can probably get his hands on one, being an engineer

i believe kiwidad used one to test the forces on his supports in the "hitchcraft for a hammock" thread. several agreed upon an equation to figure forces based on weight earlier in the thread, kd's test seemed to be in line with those findings. 30 deg angle = your bodyweight on each support.

[unknown]

I built a simple fixture to hold the come-along, scale and test piece. The come-along is rated to 2,000 lbs and the scale is rated to 10,000 lbs and in calibration. The load was always evenly applied, not shock loaded.

The test I did was with some 3.5mm Samson DuraHPS cord I picked up from eBay. It is rated to 1600 lbs. It was advertised as the same material as Amsteel. I put a bowline in each end and pulled to failure at about 700 lbs. Just about half of the rated test strength. So knots do drop the strength of cord about 50%. This material failed quickly with a snap and failed right at the knot.

Unknown

Here is a picture of the test rig and the failed cord

[warbonnetguy]

cool test, thats actually the first time i have heard of spectra actually failing at the knot where it is supposed to.

I built a simple fixture to hold the come-along, scale and test piece. The come-along is rated to 2,000 lbs and the scale is rated to 10,000 lbs and in calibration. The load was always evenly applied, not shock loaded.

The test I did was with some 3.5mm Samson DuraHPS cord I picked up from eBay. It is rated to 1600 lbs. It was advertised as the same material as Amsteel. I put a bowline in each end and pulled to failure at about 700 lbs. Just about half of the rated test strength. So knots do drop the strength of cord about 50%. This material failed quickly with a snap and failed right at the knot.

Unknown

Here is a picture of the test rig and the failed cord