Weight Load Bridge vs. Gathered End

**BrianWillan** · 09-01-2009, 17:12

Greetings Everyone

For those physics professors or quants as Grizz mentioned in one of his videos, is the bridge hammock design going to give you a greater load bearing capacity for a given fabric then a gathered end design?

From the various websites I have seen the max weight of a gathered end style hammock with 1.9 oz ripstop nylon seems to be around 250 lbs. From my logic the entire body weight is supported by the fabric on a gathered end hammock and that is transferred to the suspension. From my understanding of the bridge style hammock the body weight would be carried by the webbing or cord on the long edges of the fabric and transferred to the spreader bars and out to the suspension. Therefore, I think that a bridge style hammock would allow a given fabric to carry a greater weight than a gathered end style hammock.

Does anyone have any thoughts on my hypothesis?

Cheers

Brian

**Ramblinrev** · 09-01-2009, 18:09

By and large the HAAB hammocks like ENO and Treklight Gear are weight rated at 400#. The HH hammocks are weighted differently from 250-350 but I suspect the reason has to with suspension, not the hammock fabric. The bridge design the weight is transfered as you describe but none the less the weight is resting solely on the fabric. In short, I don't think the design of the hammock has as much to do with the weight load as the suspension does. But I'm no math genius so watch me be wrong. hehehe

**warbonnetguy** · 09-01-2009, 19:33

i don't "think" bridges would hold more. the weight seems to be distributed throughout close to the same width: say 5' wide end gathered hammock vs. the length of the person's body for a bridge. another thing to consider is the force on the fabric of a bridge hammock is transferred directly to the stitches (along the curved edge) whereas some end-gathered hammocks circumvent loading any stitches via a larkshead (although some don't), so this might put it in favor of an end gathered. spock is well over 200 and has used a single layer 1.1 end gathered for an AT thru-hike and then some, but i'd think a single 1.1 bridge hammock would show some serious stitch hole stretching in the torso region if used by someone that size. (i personally wouldn't put someone that size in an end gathered single 1.1 either though) those are the only factors i can think of, maybe someone can think of others

**Walking Bear** · 09-01-2009, 21:02

Fabric strength is one part of the bridge design. However, how the suspension triangle is designed and the spreader bars also need to be considered. All the suspension and fabric strength necessary will not work if the spreaders are not up to the load. I say that after breaking a treking pole when I had it to long on a bridge.

**Merganser** · 09-01-2009, 21:57

I would say that an "appropriately made" gathered end hammock should be stronger than a bridge just because there is no stitching in the fabric where its supporting the load. In the bridge you have stitching along the arc and that should reduce the strength somewhat.

In practice I doubt it matters because another limiting factor will come into play well before the load becomes to much for 1.9 ripstop in either case. Comfort. Nylon stretches under load and a hammock is less comfortable when the fabric is stretched significantly. This is true for either style of hammock. I go 220 and 1.9 ripstop stretches to enough under my weight that I find it uncomfortable.

I used 210D oxford DWR (3.4oz/yd) for my gathered end hammock and the stretch is pretty much unnoticeable.

I'm working a prototype bridge with 1.9 ripstop, because it was local and inexpensive, and it definitely stretches too much under my weight. I will use the 210D oxford again if I can't come up with some 2oz/yd polyester.

**BillyBob58** · 09-01-2009, 23:11

Originally Posted by Merganser

........................
In practice I doubt it matters because another limiting factor will come into play well before the load becomes to much for 1.9 ripstop in either case. Comfort. Nylon stretches under load and a hammock is less comfortable when the fabric is stretched significantly. This is true for either style of hammock. I go 220 and 1.9 ripstop stretches to enough under my weight that I find it uncomfortable.

I used 210D oxford DWR (3.4oz/yd) for my gathered end hammock and the stretch is pretty much unnoticeable. .........

Hmm, that sounded familiar, so I checked: The HH Safari is made of 210D Oxford. Maybe that is a big factor, along with roominess, in why I find it so comfortable?