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Anchoring Pioneering Projects II

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Any pioneering project that cannot safely stand by itself needs to be attached to something that will securely hold it in place. It has to be anchored. Sometimes nature will provide a tree or rock in just the right location or you might be able to shift the project’s placement to take advantage of a natural anchor. On all other occasions, anchors need to be built that will assure the structure’s stability.

Stakes – When nature does not provide a solution, anchors can be built using strong pioneering stakes. The common size of stakes for most Scout Pioneering projects is 2-1/2-inches in diameter and about 24 to 30 inches long. After cutting the stake to this size, cut a point on one end. It’s good to bevel the top edge to minimize mushrooming or splitting when the stake is driven into the ground. Long-lasting pioneering stakes are made of hardwood, such as oak or hickory.

Drive the stakes into the ground at about a 20° angle. Soil conditions can vary and will dictate how large and long a stake you need. The main thing is to make sure all stakes are deep enough so they don’t wobble or budge at all.

Under no conditions should tent pegs be used for pioneering stakes. They’re neither long or strong enough to make a safe anchor.

Page52 AnchorsMallet – When driving stakes into the ground, it’s best to use a wooden mallet. Using a metal sledge hammer can more easily damage the stake. To make a wooden mallet, cut a 4-inch diameter piece of hardwood, such as hickory, elm, or sycamore, to about 11 inches length. It should weigh about four pounds. Drill a 1-1/8 inch diameter hole to mount the handle. The handle can be made from a 24 inch length of hardwood (similar to making a stake). Use a knife or ax to round the end of the handle to fit the hole in the mallet head. Secure the handle in place with a wedge placed crosswise to the length of the head.

Guylines – When attaching a guyline, make sure its contact with the stake is as low to the ground as possible. If the guyline is placed or slips higher on the stake, there will probably be enough leverage to pull the stake loose. Guylines should be secured to the structure about 3/4 of the way up. To determine how long a guyline should be, measure the height at the point where its attached and double that distance. That’s how far away the anchor should be from the pole. For example, if the guyline is attached 10 feet up the pole, the anchor should be a minimum of 20 feet from the base.

Page53 Anchors13-2-1 Anchor – As the name implies, the 3-2-1 anchor is made by driving stakes in a series: three stakes, then two stakes, and then one stake to form the anchor. First drive in the set of three stakes. Next drive in the set of two stakes about 24 Page53 Anchors2inches away from the first set. Finally, drive a single stake in the ground about 12 inches from the two-stake set.

Connect the stakes by tying a rope from the top of the three-stake set to the bottom of the two stake set, and from the top of the two stake set to the bottom of the single stake. Use at least two loops of 1/4 inch manila rope, or six to eight loops of binder twine. Then twist the rope tight using a small stick as a tourniquet. After the rope is twisted tight, push the end of the stick in the ground to keep it from unwinding.

Depending on the strain the anchors need to withstand, you can use other configurations, such as 2-1-1, or 1-1-1, or even 1-1 for a light strain.

Log-and-Stake Anchor – This type of anchor is easy to make and can hold a considerable amount of pull. You can tie the line directly to the log, or you can use a ring with a rope grommet as shown in the photo below. To make the log-and-stake anchor, place a log 4 to 6 inches in diameter perpendicular to the pull of the line. Then drive in four large stakes in front of the log. Next, slip the rope grommet through the ring and then slip the ends of the grommet around the log. Drive a second row of stakes 24 inches behind the front stakes. Then anchor the front stakes to the rear stakes with a tourniquet made of binder twine or rope.

Page54 Anchors2

When building anchors, always be sure they are in direct alignment with the strain being applied.

Strops – When attaching lines to a natural anchor such as a tree or large rock, a strop can be used very effectively. Splice a thimble with a large ring to a 10-15-foot length of 1/2-inch diameter manila or polypropylene rope. A piece of canvas or burlap should be used to protect the rope from sharp edges of a rock or to protect the bark of the tree from rope burns.

Ring Shackle

Page45 ShortRope GrommetsRope grommets are useful when attaching a long line to an anchor of stakes. A large grommet can be made by splicing together the ends of a 10-foot length of 1/2-inch polypropylene or manila rope. If you don’t have a spliced grommet in your pioneering kit, tie the ends of the rope with a carrick bend. Be sure to secure the ends. The grommet you use must be made of a larger-diameter rope than the lines they’re connecting, to avoid creating a weak link in the chain between the structure and the anchor.

SinglePullRope grommets can be applied in a variety of configurations. In the above photo, a large ring connects the three ropes from a monkey bridge (left) to a rope that is reeved back and forth between that large ring and the ring of a rope grommet (right), which in turn is attached to the anchor.

Single-Pull, 2-Ring, Monkey Bridge Anchor Configuration

Single Pull 2-Ring Monkey Bridge Configuration

7:1 Rope Tackle Monkey Bridge Configuration
Single Pull 2-Ring Monkey Bridge Anchor Configuration

We’ve seen how block and tackles and even commercial-grade come-alongs have been employed to tighten hand and foot ropes during the construction of various monkey bridge projects, especially those spanning longer distances and using larger diameter ropes. On the other side of the coin, in the presentation of his Double A-Frame Monkey Bridge, Adolph Peschke says, “Whatever strain three or four Scouts can put on the foot rope by pulling it by hand will be enough.”

The simple rope tackle provides a 2:1 mechanical advantage and is frequently used to apply the desired tension to both hand ropes and foot rope—often on both sides of the bridge. Adjusting the strain on individual ropes during use of the bridge can result in a slight complication—the spanner ropes can lose their symmetry.

7to1RopeTackleBridgeEnd
On the side of the bridge where the tension will be adjusted, the hand and foot Ropes are attached to one large ring.

A method that will alleviate this issue, and also provide a greatly increased mechanical advantage, is to utilize a Single Pull 2-Ring Configuration. After attaching the hand ropes to their respective spars with Clove Hitches, (adjusting the strain on the sections of the hand ropes between the double A-frames to match the sag of the foot rope) this approach is executed as follows:

  • Use a roundturn with two half hitches to attach the hand and foot ropes to a rope grommet at one anchor point. At that side of the bridge, they will remain fixed.
  • Pulling the three ropes so each receives the same degree of strain, attach each to one large ring at the other side of the bridge, again using Roundturns with Two Half Hitches.
  • With a length of 1/4 or 3/8-inch manila (preferred), using a roundturn with two half hitches, connect one end to the same large ring.
  • The other ring is in the rope grommet which is attached to the anchor.
    The other ring is in the rope grommet which is attached to the anchor.

    Reeve the running end of this rope through the ring in a rope grommet which is situated about four feet away and already fixed at the anchor point on this side of the bridge.

  • Carry the running end back and reeve it through the large ring. (If you now pull on the running end, there’s a 2:1 mechanical advantage.)
  • To increase the strength of this connection enabling it to withstand all the strain exerted on the bridge during heavy operation, reeve the running end back through the ring in the rope grommet and then through the large ring two or more times.
  • Now when you adjust the tension of the hand and foot ropes with this pull rope, the mechanical advantage is greatly increased. Secure the entire configuration with two Half Hitches cinched up against one of the rings.

Some Notes: This arrangement can be configured any way you like, e.g. when using 3/8-inch manila, attach the pull rope to the large ring, reeve it through both rings twice, and then finally secure the configuration at the large ring. Or, instead of first tying the pull rope to the large ring (the ring that’s functioning as the moving block) initially tie it to the ring in the rope grommet (fixed block). Then proceed to reeve it through the other ring, back again, etc.

With each turn on the rings, make sure the rope doesn’t cross on top of itself as this would interfere with adjusting the strain.

This kind of rope tackle can exert too much force on the bridge components, so carefully monitor how tight everything is getting and don’t just give the rope a willy-nilly pull.