Bridge Side Cuts and Flatness

[TeeDee]

I had forgotten that post of TeeDee's, it deserves a bump.

Also I mis-remembered the width of the BMBH, it is 37" at the middle, not 39".
The fabric length under the spreader bar is 53", so the cut is 8".

The BMBH spreader bar is 31", but slot-edge to slot-edge it is 30.25". Then consider that these slots are in 2" diameter rings that are forced to be largely horizontal under load, so the actual spread in the hammock body is closer to 28".


Grizz

Hmmmm - That puts the ratio of spreader to fabric, 28/53 == 0.53 or 30.25/53 == 0.57

My experiments with people indicated that a ratio less than 70% was uncomfortable for everybody tested. They expressed discomfort with what is commonly known as shoulder squeeze. That forced me to a minimum ratio of 0.70.

But the side to side stability suffered until I made the foot end ratio 0.50 to 0.60. The side to side stability was then acceptable to everybody.

[JerryW]

My experiments with people indicated that a ratio less than 70% was uncomfortable for everybody tested. They expressed discomfort with what is commonly known as shoulder squeeze. That forced me to a minimum ratio of 0.70.

But the side to side stability suffered until I made the foot end ratio 0.50 to 0.60. The side to side stability was then acceptable to everybody.

Well that settles it for me. Last night I re-cut my tester to an 9" curve. I didn't notice a huge difference from the 6" curve I had tried. So I did a little figuring and sketching and came up with a finished size of 45" wide with a 6" curve, giving a center width of 33". This ends up an inch wider than yours and a few inches narrower than one of Grizz's and Walking Bear's.

With my proposed spreader bars of 32" and 24", that makes the head end ratio .71 and the foot end ratio .53. Sounds like a winner to me. Once my fabric arrives, that's what I'm going to go with.

Thanks for all the input everyone!

Jerry

[JDShearer]

Hi, this is another newbie chiming in. I'm loving all this info on bridge hammocks, and I'm trying to finish my first diy one. My initial design was a wide one: I really don't want shoulder squeeze. I also figured I can always cut it smaller, but I can't make it bigger. Anyhow, the fabric's about 60" wide at the spread point. I hung in it the other day with a 48" head end spreader and a 37" foot end spreader and felt like it was still very deep and like I was still really getting shoulder squeeze. Is the only problem with spreading it tighter than this stability? I still felt very stable hanging with these dimensions. Oh...and I realize this is a ridiculously wide design and I am planning to slim it down to use with my 37" spreader bars. Any thoughts would be appreciated, and I want to say that I really appreciate this community. Thanks!

[slowhike]

Welcome to HF JDShearer.
I'm sure the bridge hammock folks will be glad to help w/ your project when they see your post.

[GrizzlyAdams]

Hi, this is another newbie chiming in. I'm loving all this info on bridge hammocks, and I'm trying to finish my first diy one. My initial design was a wide one: I really don't want shoulder squeeze. I also figured I can always cut it smaller, but I can't make it bigger. Anyhow, the fabric's about 60" wide at the spread point. I hung in it the other day with a 48" head end spreader and a 37" foot end spreader and felt like it was still very deep and like I was still really getting shoulder squeeze. Is the only problem with spreading it tighter than this stability? I still felt very stable hanging with these dimensions. Oh...and I realize this is a ridiculously wide design and I am planning to slim it down to use with my 37" spreader bars. Any thoughts would be appreciated, and I want to say that I really appreciate this community. Thanks!

Welcome JDShearer.
Conventional wisdom is that the ratio of spreader bar length to fabric beneath is a good indicator of flatness, the larger the ratio, the flatter
the lay. I use 36 inches over 48-50 inches for a ratio close to 0.75. Yours is higher still, at 0.8. What you may be feeling is what I call "shoulder presence", that is, it feels different laying in a bridge hammock, it is closer around you. You want to know what shoulder squeeze feels, try putting in a 24" spreader bar!

My first DIY bridge was also 60" wide in fabric, and had 12" suspension cuts. The sides of the hammock soared above my head, it seemed. One of the
things I like about a shallower hammock is that I don't feel like I'm at the bottom of a bathtub.

Looking forward to hearing more of your bridge experiences

[JDShearer]

So I guess my question has become: how tightly can I spread my bridge before the hammock becomes too unstable to sleep in? Has anyone spread one more than .8 bar/fabric? For reference, this is my current hammock. Not a bridge, I know, but spread tightly, and I have no problem with tipsy-ness.