Introduction: 3-point Tie-down Anchors (static & Dynamic)

Picture of 3-point Tie-down Anchors (static & Dynamic)

This tutorial will show how to create static and dynamic 3-point tie-down anchors for securing popup tent canopies, RV awnings, etc, for windy situations. I will show you how to create a static tie-down for routine situations and dynamic tie-downs (variable tension) for such things as RV awnings. Both styles of anchors are light-weight, low cost, easy to setup and the components can be used for other applications as well when camping – I like multiple use items when camping!

Some soil conditions are not favorable for many of the types of anchoring systems available, such as single tent stakes, auger devices, and/or screw in type (pet tie-down). For example, each year we attend the Buckley Old Engine Show near Buckley, Michigan where the soil conditions make it difficult to use RV awning tie-downs. The soil has a 6-inch top layer of loosely packed soil/sand mixture with gravel and/or hard clay below that. Augers and screw-in anchors usually can’t hold in the loose soil layer and have difficulty penetrating the hard clay (screw-in anchors  tend to snap off when attempting to screw into the hard clay). Several of our friends have resorted to using water jugs and concrete blocks as tie-downs – bulky, but they work.

Three years ago I acquired “The Claw” anchor devices and I have had good results when using in the Buckley soil. For the last two years our friends have struggled with their tie-downs, so earlier this year I created a solution for them based upon a 3-point tie-down anchor. Since they have been using the dynamic anchor versions they’ve told me they won’t use anything else, no matter where they camp. Because my friends liked them so much I’ve decided to make this instructable available to others.

Cautions:
1) These tie-down anchors are ‘shared load’ rather that ‘distributed load’ anchor devices, therefore I don’t recommend them for climbing.
2) Since both “footprints” can present potential trip hazards, I recommend attaching something brightly colored to the anchor “feet” to make them more noticeable.

Step 1: Tools & Materials

Picture of Tools & Materials

Tools for dynamic 3-point anchors

- drill or drill press

- ¼ “ drill bit

- wrench

 

Materials for dynamic 3-point anchors

Quantity                   Part Description                   Approx Cost

3                              15” EPDM rubber straps                $ 4.50

3                              10” tent stakes                             $ 3.50

2                               ¼ ” x 1 ½ “ fender washers           $ 0.58

1                               ¼ ” x 2 “ eyebolt (zinc) with nut     $ 0.39

1                               ¼ ” lock nut                                 $ 0.10

 

Materials for static 3-point anchors

Quantity                   Part Description                   Approx Cost

3                              10” tent stakes                             $ 3.50

10 ft                          ¼ “ rope                                      $ 1.50


Step 2: Creating a Static 3-point Tie-down Anchor

Picture of Creating a Static 3-point Tie-down Anchor

Starting with the 10-foot rope, tie the ends together using a standard overhand knot. Partially insert a tent stake into the ground to use in the next few steps. Place the knotted end in one hand and wrap the rope around the tent stake and bring back to your hand; hold with a few fingers and adjust the free end of the rope until it reaches back to the tent stake (see photos). Place the free end of the rope over the tent stake (see photo) and then tie the rope ends in your hand into an overhand knot (see photos). You should end up with the original knotted ends, two small loops, and three 12-inch loops. You can now remove the rope from the tent stake.

To use this 3-point tie-down anchor, lay the anchor in a triangle formation and drive the tent stakes into the ground at a 45-degree angle towards the center of the anchor (see photo). Make sure the loops are taut before driving in the last tent stake. Use the two smaller loops of the anchor to attach your tie-down rope, ratchet, etc.

Step 3: Creating a Dynamic 3-point Tie-down Anchor

Picture of Creating a Dynamic 3-point Tie-down Anchor

Take two ¼ “ fender washers and drill three ¼ “ holes through the washers as shown in the photos – be sure the holes lineup with each other on the washers. Attach the fender washers to the eye bolt using the nut that came with the eye bolt and a ¼ “ lock nut (see photos).

Remove an “S” hook from each of the EPDM rubber straps and bend the smaller ends 90 degrees (see photo). Re-attach the “S” hooks to the rubber straps (see photo).

To use, insert the angled “S” hooks into the holes of the fender washers and layout in a triangle formation – for safety, be sure to point the “S” hook ends pointing downward. Position and the tent stakes about 2 inches from the ends of the strap hooks and drive the tent stakes in at a 45 degree angle towards the center of the anchor. Stretch the rubber straps and attach the “S” hooks around the tent stakes. Use the eye bolt to attach your tie-down rope, ratchet, etc.

Step 4: Testing the Anchor Strengths

Picture of Testing the Anchor Strengths

All that’s left is to test the anchors. For the test above I chose poor soil conditions with a poor grass root structure. As can be seen in each of the photos, there was no movement of the tent stakes at 25 & 50 pounds of pull since the load is shared by each of the tent stakes. Under normal conditions, the maximum tension recommended for RV awnings is no more than 50 pounds. The test photos show the results at around both weights - the tape measure in the photos is to show the amount of upward deflection at each weight.

I wasn’t able to find any recommended/maximum tension figures for popup tent canopies, but I suspect they would be similar to RV awnings – maybe even less.

Dynamic versus static anchors
I’ve read numerous articles/comments on whether to use tension springs or not – no one seems to have done any definitive test results. However, I did find an article with comments that leads me to believe if you need to use RV awning tie-down anchors in windy conditions it is probably best to use dynamic anchors rather than static anchors. Therefore, I included both in this instructable. 

Comments

Henge (author)2013-02-10

This is great, I will definately be employing this idea into my tent and tarp regiment.

Lorddrake (author)2011-09-09

awesome idea. thanks for sharing.

zazenergy (author)2011-09-08

Thank you for sharing this! So helpful for when I go camping next!

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