How Much Weight Can a Hammock or Tree Handle?

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So your brand new hammock just arrived, and you’re all set to string it up for the first time. Great! But how can you be sure that your hang is safe? How much force can that spindly sapling in your back yard really handle? And is it safe for two people to hang together? Here are some fundamentals, tips, and tricks for ensuring your hammock hang is safe, granting you the peace of mind to relax and fully enjoy one of the most comfortable pieces of furniture in existence.

Suspension Safety: Weight Capacity
Every hammock produced by a reputable manufacturer will arrive with documentation specifying a safe weight capacity limit. For La Siesta’s 2015 hammock line, the specified weight capacity ranges between roughly 265 and 440 lbs, depending on the type of hammock (traditional cotton, parachute nylon travel, woven Mayan, etc.). Though you might be able to exceed these weight limits without damaging your hammock, it is just not worth the risk of injury to find out.

Similarly, every suspension system will also have a stated weight capacity. La Siesta’s 2015 Tree Rope hammock hook suspension is rated at 440 lbs. All weight capacity specifications, for both hammocks and suspensions, are stated assuming normal casual loading behavior. Bouncing or extreme rocking could create large forces that might hurt you or your gear. Just use common sense and you’ll be fine.

Hammock Safety: Weight Distribution
When lying in a hammock, it is always a good idea to empty your pockets of anything sharp or abrasive. Not only will this increase your lounging comfort, but it will also lessen the likelihood that your hammock will develop runs, punctures, or tears that could de-rate the hammock’s weight capacity. It’s also recommended that, when entering and exiting the hammock, you apply weight to the broadest area of fabric possible. Applying all of your body weight to a small strip of edge fabric could result in unexpectedly high forces and hammock damage. By spreading the hammock fabric out behind you as you sit down, you can distribute your weight more evenly and enjoy your hammock for years to come.

Tree Safety: Tree Sizes
Before your hammock even comes out of its bag, you first need to select a good pair of trees. The trees should be approximately 12 to 15 feet apart, thick enough to sustain your weight, and healthy.

Minimum safe trunk thickness is dependent on a variety of factors. First of all, different species of tree have different relative break strengths. Equipping yourself with the knowledge of which native species are the strongest may be a benefit. If in doubt, go larger. I generally target trees with diameter of 12” or greater, although I have successfully used smaller-diameter trees. If your selected trees are less than 12” in diameter, pay attention to bending displacement as you enter and exit your hammock. If the tree trunk deflects more than 1” at eye level when loaded, you should find a different tree. Additionally, audible creaking should be taken as an obvious sign to change locations.

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Tree Safety: Angles and Force
One of the most-overlooked facts of hammocking is the role that the angle of your suspension plays in determining the magnitude of the forces applied to the trees. I won’t get into the trigonometry here, but the critical takeaway is this: the flatter your hammock is set up (the more horizontal your suspension lines are), the more force is applied to the trees.

On a hammock hanging at a 30-degree suspension angle from horizontal, a 200-lb person creates a tension of 200 lbs in each suspension line. At a 5-degree suspension angle, however, a 200-lb person creates a tension of 1,147 lbs in each suspension line!  Not only is that a huge amount of tension, but also it restricts your position in the hammock to lying lengthwise, instead of a comfortable diagonal position.

So, if you feel that your hammock, suspension, or trees are under too much load, try loosening your suspension to create more sag in your hammock. Doing so can drastically reduce the forces applied to your hammock system.

Tree Safety: Warning Signs
Diseased or compromised trees could fail unexpectedly, so be sure not to set up beneath a tree that exhibits any of these warning signs:

  • Leafless or dead-leaf-bearing branches out of season
  • Cracking at branch points
  • Sloughing off bark
  • Visible fungus
  • Significant animal use

Ultimately, if there is any question whether a tree is in good health, find another place to hang.

#1 Rule of Safety
You may have the perfect hammock, a top-notch suspension, and two healthy, sturdy trees. But, at the end of the day, what is the most important single thing you can do to stay safe in a hammock? Only hang your hammock as high as you are willing to fall. 18 inches above the ground is the perfect height for use both as a chair and a bed. Why hang higher?

There are many ways to sit in a hammock. How many of them do you know?

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