March 18, 2006
Length and width of the hammock as a proportion of body height
Theory: hammock characteristics based on length and width are proportional to the body height of the person using the hammock. Assumption: that the hammocks which are being compared are made the same way, such as by knotting the ends (measure from the inside of the knot to the inside of the knot) or bundled and bound (measure from the inside of the binding to inside of the binding).
If you take the height of a person, and make a hammock for them cut out of cloth of a certain length, you can calculate the hammock length as a percentage of the person's height.
For example, a six foot person (72") and a hammock cut at eight feet (96") long and just under five feet (58") wide:
Length: 96/72 = 1.33 or 133% body height
Width: 58/72 = 80.05 or 80% body height
Different length hammocks have different characteristics. The example is a short hammock, probably close to the minimum length hammock that is comfortable. So if the theory is correct, a five foot tall person would experience a similar level of comfort in a hammock cut to a length of 80" (60" * 133% = 80").
If the theory is correct, then I can test different hammock sizes and report the results based on hammock sizes as a proportion of my body height, and any reader can use his own body height and get a meaningful result by calculating hammock sizes.
Hem and loop hammock support system
I made a canvas hammock for my boat, and tested a system of tying a support line around the end of the hammock. On the other end, I used a slip bowline to make a loop at the correct location and put the loop around a toggle on a tree hugger. A more detailed description follows:
This system seems to work on a canvas hammock with just a single fold hem, and it may work on a nylon hammock with the double/triple hem described above as well. The slip bowline has been relatively easy to untie, unlike a simple overhand loop which became a permanent part of my rope after hanging for a while. The tree hugger/toggle system is an attempt to create a system which can be broken down quickly. When cold weather camping, it is important to be able to break camp quickly in the cold cold morning frost. This system requires no untying of knots, just pull the toggle out of the loops and unwrap the tree huggers. Leave the slip bowlines in until later. You can break the hammock down quickly, even while wearing your gloves.
This system has been tested indoors with a canvas hammock. I hope to build a single layer 1.9oz uncoated nylon ripstop hammock with this system and test it. I am leaning toward camouflage color and a full 60" width hammock. I may start out with a 200% body length hammock (12 feet) to see if there is additional comfort from a large hammock. That length may be difficult to cover with a tarp, and it has some additional weight. I am curious if bigger is better when it comes to hammock comfort.
pad liner pad doubling system
From joei4515 at the yahoo hammock camping list:
"Paul, Here is what I did for the configuration you want. Based on using a 20" wide by 1/2" thick CC pad, I cut two pieces of material to 22" wide by 5' long (I used a Neat Sheet found on sale at WalMart, but any material will do). I sewed a hem on each to prevent fraying, then sewed both together at the head end and down about 8" on each side so that I only have one thickness under my head. I left a 21" gap, made a tack on each side, left a 21" gap, then sewed the sides together down to the bottom, leaving the bottom open to insert the full length pad. I then inserted a 36" piece of pad through each of the openings from the side. This gives me a 40" long double thickness from my shoulders to below my hips and a single thickness down to my feet plus 8" wings on each side. You could modify this by cutting the second pad shorter in length and width. The weight of my material is 6 oz. Add in the weight of the two pads (24 oz) and I have a 30 oz insulating system. Yes, I know you can buy or make underquilts that will save you weight and volume, but can you find them for around $12 and still provide comfort if you need to go to ground (or worse yet, sleep on a wooden platform)? Good luck with your project."
I built a pad liner pad doubling system out of canvas, and hope to test it in the field soon. It seems to be a good solution. It does not seem to require a double layer hammock, it seems to stay in place pretty well.
Pod and condensation
One of my concerns when cold weather camping is condensation and the resulting chill when you get out of the sleeping bag. I want to test to what extent the pod (a full hammock enclosure made of nylon ripstop with zippers) causes condensation. This should be tested in wind conditions and no wind conditions. Another variable to test is using a closed cell pad vs. an underquilt.
The question is if the pod can be used in all conditions or if it is best suited to only windy conditions below a certain temperature. My theory is that the pod should only be used in no wind conditions when the temps are under 40F. In windy conditions, the pod may be used at any temperature.
Condensation and ambient temperatures
I have a theory that condensation is worst at 32F, and as the temperature rises it becomes less and less of a problem. Above 55F it is not as much of a problem. Below 32F the air becomes drier but condensation can form easily on a vapor barrier around the sleeper.
I have only hammocked in sub-35F conditions so I don't know if condensation is a problem at warmer temperatures.
I appreciate any comments and advice on achieving comfort in a hammock system.
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