Intro: How to Make a Cot Style Hammock
After spending a night in a bunched end hammock and feeling a little cramped I decided to create a flatter hammock. This Instructable is the result of my efforts. The hammock was designed with my sleeping bag system (not yet published) in mind. When used in conjunction with my sleeping bag system it will have an attached under-quilt and a channel for a sleeping pad. The hammock can be used on its own as well. Feel free to simplify the design if you will not need the attachment points on the sides. Having the rope exposed only at the center point of each side should meet most people's purposes.
This project can be completed in one weekend.
This hammock can be set up using 2, 3, or 4 tension lines. Using 2 tension lines (between 2 trees) will generally require at least 2 tie downs for stability while 3 or more tension lines will not. Attaching one end to a tree that is wider than the hammock width will also create a stable configuration (it's almost like tying at 3 points.). By using the rope access points on the sides, the hammock could be attached to a frame and used as a cot.
Step 1: Materials and Tools
1.5oz or stronger ripstop nylon.
I purchased the nylon in a fabric store. The width of the roll from the fabric store was 59 inches. You will need to order your material based on the length of your hammock. I bought 2.5 yards (90 inches) for a hammock that is 78 inches long.
2 pieces of 7/8 inch rigid copper tube slightly shorter than the width of the hammock.
The length of the tube will be slightly less than the final width of the hammock. You will need to get a length of tube about twice the length of the hammock. Initially I searched for aluminum tubing but did not find any so I settled upon copper. I like the copper now, It looks awesome and was easy to work with. Feel free to substitute aluminum or anything else you think may work.
2 pieces of 1 1/4 inch PVCslightly shorter than the width of the hammock.
Rope for frame:
You need something that will not stretch. (Paracord is NOT a good choice.) I used hollow braid polypropoylene rope that is rated for 215 lbs. A rating of around 115 lbs would probably work fine since the weight is distributed among the 2 ropes and 4 tie offs.
Cord for tie downs
I used a 40lb nylon and polypropylene cord as optional tie down straps.
Heavy duty polyester thread. This is often called outdoor thread.
Note: The size and strength of the rope and rods I used is based on a person near 150lbs. You may need stronger tubes on the end if you are a larger person. I have not tested it with a larger load than my own weight. I suspect it can hold a lot more but experimentation is recommended. If you place a piece of material that is the width of the hammock between two points and it can support more than half your body weight it should be fine to use.
ball peen hammer (for copper)
hammer (for copper)
knife (for pvc tube)
Step 2: Sizing and Cutting Your Material
The first step is to determine where to cut the ripstop nylon. I wanted my hammock a certain size so it would work with my sleeping bag system. Prior to cutting I came up with the following formula to get an idea of where to cut the material. I did not calculate where the material comes off the tube at a tangent or its exact length there but instead added an extra diameter. There should be excess material using the formula below. Excess material can be compensated for by making the overlap larger. If you are uncertain give yourself a little extra material to work with.
Desired length = 78 inches
Size of the edge hem = 1/4 inch
Diameter of tube = 7/8 inch
Overlap = 1 inch
desired length + (((size of edge hem * 2) + circumference of tube + diameter of tube + overlap ) *2)
78 + (((0.25 * 2) + 2.75 + 0.875 + 1) *2)
78 + (0.5 + 2.75 + 0.875 + 1) *2)
78 + 10.25
88 1/4 inches
My material size was near 89.5 inches when I trimmed it. I just used this length and added a longer overlap on the ends.
Desired width = 26 inches
Size of the edge hem = 1/4 inch
Diameter of rope = 3/8 inch
Overlap = 1/2 inch
desired width + (((size of edge hem * 2) + circumference of rope + diameter of rope + overlap ) *2)
26 + (((1/4 * 2) + 1.18 + 3/8 + 1/2 )*2
26 + (0.5 + 1.18 + 0.375 + 0.5) *2
26 + 5.11
To calculate the circumference of the tube or rope, use the following formula.
Circumference = pi * diameter
If you get material in a store the cuts may not be exact. The cuts could be on a slight angle or you may get slightly less or more material. I bought 2.5 yards of material which is 90 inches. After straightening the edges I had just enough material to make the hammock. If you are as close as I was to the cut point you may wish to get a little extra material.
Since the width of the material I bought was 59 inches I decided to make the width of the hammock slightly shorter so that I could get two hammocks out of the material. I cut the material directly in half at 29.5 inches and use slighty smaller edge folds and overlaps.
Step 3: Hem the Edges
For this section I am assuming a 1/4 inch hem. Replace the measurements as needed.
Using a weak glue to secure the hem in place will make sewing easier.
Place glue on the outer 1/2 inch of material.
Fold 1/4 inch of material over.
Repeat this process.
Using outdoor thread, Sew a line close to the open end of the hem. This will be a little less than 1/4 inch from the edge of the material.
Follow this procedure for all four edges of the material.
Step 4: Mark the Fold and Cut Lines on the Ends.
Making the fold lines.
Each end of the hammock will need to be folded over the tube and attached. If you have a desired length for your hammock then you will need to measure the length of the hammock and subtract your desired length. For example.
88-78 =10 inches
Mark a line with chalk at 5 inches on each end.
If you are not concerned with measurements, just fold the material over your tube and mark the material with chalk.
Leave a little extra material so there isn't a lot of stress on the last sew line and so the tube can slide in and out easily.
Follow the same procedure as above but use the rope instead of the tube.
Making the cut lines:
To create a stronger hammock we will need to hem the places where the tube and the rope are pulled through. Ideally we want to do this so there are no exposed cut edges. If you have an inch of overlap (the part you will sew together to attach the end) then the cut line should be less than an inch away from the fold line. Refer to the pictures. The next step will help to clarify why this cut is being made where it is being made.
Step 5: Hem the Tube and Rope Entry Points
Using the 2 flaps of material cut loose in the previous step create two hems as shown in the first picture. Create two or three parallel sew lines on these hems.
We are trying to achieve something that looks like the second picture. The material is just folded over in the second picture for demonstration and has not yet been attached.
Step 6: Create the Rope Attachment Points
I designed the hammock so that I can attach an under-quilt or other sleeping gear to it. There are 7 points on either side where the rope is exposed. The length of the hammock is divided into 8th to determine the points. If you don't need that many connection points I would recommend to at least expose the rope at the halfway point. Stabilizing tie downs can be used there when the hammock is only connected to two tension lines.
Mark an 'I' at each of the locations you have determined to place a hole. See the first picture. The width of the holes I made were 2 inches. Do not cut too close to the edge of the fabric. The distance from the edge of the fabric should be minimally larger than the size of the overlap you planned.
Cut along the 'I' pattern.
Using the flaps of material, fold them over twice to create a hem. Use the stick glue then sew like was shown previously. Create two or three parallel sew lines on this hem.
The third picture shows what your material should look like after the holes are cut and hemmed.
Step 7: Create the Rope Channel on the Sides.
Fold the sides of the hammock material over to meet your attachment line (drawn in an earlier step).
Place your rope or one slightly thicker in the rope channel. This will serve as a stop guide for your sewing machine foot. It will prevent you from making the channel too narrow.
Create the first line of stitches closest to the rope
Once the first line of stitches is done you can then remove the rope and create two or more parallel stitches. More is not necessarily better unless you have a large overlap. Too many stitches close together can weaken the fabric.
Step 8: Add Reinforcement Strips
When we made the holes to expose the rope a cut fabric end was exposed. We want to cover that end and reinforce the material so a rip can not form.
I am using a piece of leather in the picture but this is because I did not have any excess ripstop nylon. After doing this I think the leather may actually be a better choice since I did not have to worry about the cut edges.
You will need a piece of material twice the width of the overlap and an inch longer than the length.
The width of the overlap is 1/2 inch and my strip is an inch wide.
The hole length is 2 inches and the length of my strip is 3 inches.
With the back of the material facing up, center the material under the hole.
Mark where the edges of the hole are.
Fold the material in half and cut to the point where you marked.
Fold the material over the exposed nylon edge as shown.
Sew the material to the nylon. Be careful not to narrow your rope channel. Use the previous sew line as a guide.
Your project should look similar to the last picture now.
Time to get a break from sewing and head off to the shop.
Step 9: Create Copper End Bars
I used 7/8 inch rigid copper tube to form the end bars. I chose copper because the PVC from a previous trial bent under my weight. I also could not find aluminum poles to use.
Measure and mark the pipe an inch shorter than the width of your hammock. For a 26 inch wide hammock cut two 25 inch pieces of pipe.
The ends of the pipe need to be rounded off to prevent them from digging into the rope. This can be done using a ball peen hammer or even a steel ball. I performed this step on an old carpet on a concrete floor. I placed the end of the pipe on the carpet and held the pipe in place between my knees. Next I held the ball peen hammer in place as shown in the picture. Using another hammer I pounded down on the ball peen hammer until the edges began to flange out. I would flip the pipe over occasionally to work both ends. The downward force on the concrete also helped to flange out the ends.
After the edges were flanged out I used the hammer to bend the edges back towards the pipe. This created a lip on the end of the pipe.
When I was done hammering the lip I filed off any sharp spots and then sanded everything with emory cloth.
Warning: If in the process of flanging, the end of the copper tube splits even slightly than the tube can not be used in the project. Any flaw or split in the tube will result in failure. This happened to one of my tubes, I thought "I can replace it later" but it didn't take long for it to fail. See the last picture.
Step 10: Create PVC Ends
This step is an alternative to the copper ends. Using PVC will require a thinker diameter tube to support the same weight as a copper tube. I used a 1 1/4 inch tube. My hammock currently has one copper end and one PVC end.
Note: The pictures are from a smaller diameter tube but the methodology is the same for preparing the tube.
Measure and mark the tube an inch shorter than the width of your hammock.
With a sharp knife, cut away the sharp edge on the inside and outside of the circle.
Round off the end of the tube with sandpaper. The end should be as close to a half toroid as possible.
Step 11: Attach the Ends
Ok, Back to sewing. You're almost done!
Fold over the end of the hammock to meet the line you calculated prior to cutting the end. Attach the overlap with multiple lines of stitching. If you don't have a lot of material you may put your pipe in the fold to keep the channel from being sewn too narrow.
Step 12: Thread the Rope
Install the prepared pipes in the ends of the hammock and thread the rope as shown in one of the diagrams.
Sometimes rope will come with a rope threading needle. I have shown this in the picture but found it wasn't really necessary to use.
There are two methods shown to thread the rope. The first method could make it more difficult to hang the hammock if you do not have the ends lined up parallel when you set it up. The second method of threading the hammock will require you to thread the hammock under tension so you can measure exactly how much rope you will need in the centre loop.
To thread the hammock with 3 segments of rope.
1) Thread the end tubes first.
2) Set up the hammock so it is very taunt.
3) Thread the inner ring of rope.
4) Put two marks on where the ends of the inner rope cross so you know where to tie it.
5) loosen the ends slightly.
6) Tie the inner rope so it is slightly shorter than the points you marked. This will enable the rope to create greater tension on the hammock making it flatter when you use it.
Step 13: Make Loops at the End of the Ropes
Creating a loop at the end of the ropes will give us a quick way to attach tree straps.
Use a bowline knot to do this.
Step 14: Time to Use the Hammock.
Job well done. Now It's time to go camping.
The diagram shows various ways to set up the hammock.
The best configurations are to attached the hammock to 3 or 4 points. Using four points effectively creates a stable platform.
Two point configurations will require stabilizer ropes attached to the ground. I selected 40 lb test ropes for this.
I did not have anyone available to take a picture of me in the hammock but I've included a picture of my feet and some rocks for your amusement.
The trees in the images were a little too close together which limited how much tension I could put on the hammock.
I am happy with the results of this project so far. I will be doing more testing of this design and if I come up with any changes or improvements I will add them to this Instructable. If you attempt this project please share your results with me.
Step 15: Additional Photos
Here are some pictures of my sleeping set up.
I have a sheet, fleece/poncho and quilt (not shown) that can be tied together.
The hammock can slide into the sleeping gear. There are attachment points on the sheet, fleece and quilt that line up with the hammock attachment points. This gives the option to tie all the gear together.
A channel is formed between the sheet and hammock so a reflective pad can be inserted.
I will be uploading instructions for the sleeping gear eventually.
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