Tag Archives: Mark II Square Lashing

Square Lashing as presented in Bryan on Scouting

As presented in Bryan on Scouting:

Always tie a square knot correctly with this tip

Tying a square knot might be confusing for Scouts. “Right-over-left” or was it “left-over-right?”

For the next few weeks, we’ll be sharing some camp hacks that the BSA’s national camping subcommittee has shared with us. This week’s tip involves a technique to tying a square knot correctly every time. Special thanks to Larry Green for the tips and text below.


The square knot, also known as the reef knot, is first and foremost a binding knot. Its primary function is to secure a line tightly up against an object as when tying a bandage, a package or the flaps of a wall tent at camp.

When it’s time to tie a square knot, there’s a surefire way to always tie it right, and all you need to do is use your eyes.

  1. Tie the first half-knot.
  2. Position the ends so the blue end projects down on one side, and the red end extends up on the other side. It’s as if each end has its own area — like each is in their own “zone.” That’s where they need to stay.
  3. When the ends are brought together to form the second half-knot, they don’t enter the other “zone” by crossing behind the other end. They just meet in the middle. The knot is finished by carrying either end over and around the other.
  4. It makes no difference how the first half-knot is tied (over-under or under-over, right-over-left or left-over-right).
  5. When bringing the ends together to form the second half-knot, keep them in their own “zones.” Don’t cross over into the other end’s area.
  6. This way, you’ll always tie a square knot, and never a granny knot.

Tying a square knot from this visual perspective comes in handy, because often Scouts will lose track of whether they went over-under or under-over, or right-over-left or left-over-right. Once they get the knack of seeing how each end stays in its own “zone,” this approach is fool-proof.

Watch the video of this technique below.

Japanese Mark II Square Lashing in Boy Scout Handbook!

After being excluded in all previous editions, the 13th Edition of The Boy Scout Handbook features the Japanese Mark II Square Lashing—a very good thing! Referred to simply as “The Mark II Square Lashing,” it’s included along with the other lashings in Chapter 12.

Many different things, both big and small, contribute to increasing the BSA’s rate of retention. In its own seemingly small, but unique and interesting way, this lashing is an actual example. On several occasions, I’ve heard adults and older Scouts remark they wish they knew this lashing when they were a Scout or when they were younger—and if they had, they would have done more pioneering. When it comes to pioneering, the Mark II Square Lashing increases Scouts’ willingness, receptivity, and most of all ability to readily become active in this timeless Scouting activity. Troops definitely become more able to embrace the many rewarding Pioneering Skill Challenges that contribute to making Scout meetings fun with positive outcomes.

Compared to the clove hitch method, Scouts love it. It’s much more simple to tie and some declare it’s even easier to make tight. After he attended a pioneering training session at the 2015 NOAC at Michigan State University, celebrating the 100th year anniversary of the Order of the Arrow, one appreciative adult, who had not yet been acquainted with this lashing was heard to remark, “If I gain nothing else during the week, the fact I learned this lashing will be enough.”

The sad part has been, during district, council and area events, simply because they tied a lashing that wasn’t in the handbook, Scouts have been disqualified, penalized, and even insulted, resulting in confusion, hurt feelings, and disillusionment. That’s why, in the 13th edition there should be absolutely no doubt that the Mark II Square Lashing IS a square lashing and NOT an “alternative to the square lashing.” (first printing page 374) That way when it’s stipulated that square lashings are required for a Scouting competition, there’s no confusion! Any Scout or Scouter involved in the building of pioneering projects throughout the year tie square lashings all the time. To most all of them, the Mark II Square Lashing is what is tied whenever a square lashing is tied. Period. For many, that’s how it’s been for all their years as an adult volunteer—happily involved in unit to national-level pioneering programs.

The following is a copy of what was initially submitted through the Boy Scout Development Task Force as an addition to or replacement for page 396 in the 12th Edition of the Boy Scout Handbook. (What’s included in the first printing of the 13th edition has no photographs, but the content is correctly presented.):

Mark II

Double A-Frame Monkey Bridge

—> View Video of Bridge Construction

Assembly
Adjusting knots and lashings after the first test crossing.

The well-known, time-tested, traditional Monkey Bridge is perhaps the most familiar of all Scout pioneering projects. It’s frequently featured at Scout Expos, Camporees, Scout Camps, and is often a central attraction at public gatherings where Scouting is represented.

The following instructions and guidelines are provided by Adolph Peschke, taken from the 1993 edition of the Pioneering Merit Badge Pamphlet:

Link to: Older Pamphlet InfoUsing a double A-frame to build a monkey bridge is a departure from the usual X-frame that supports the foot rope and hand ropes. This new method has two distinct advantages over the X- frame version. First, the double A-frame provides a wider base making it less likely to tip over. The second advantage is that the positions of the A-frames can be adjusted so the span between the hand ropes can be narrowed for better balance as you make the crossing.

Building the A-frames. The first step in building the monkey bridge is to build four A-frames using the 8-foot spars for the two legs, and 6-foot spars for the ledger. Lay out the first set of three spars (two legs and one ledger) on the ground in position for lashing. Before lashing, drive three stakes, as follows, to help you make all four A-frames the same size: Drive a stake at the top to mark where the leg spars cross. Then drive stakes to mark the positions of where the bottom ledger crosses the legs. This will also indicate how far the legs are spread apart. Now you can lash the four A-frames together, laying them out one at a time using the stakes. Remember that all three lashings on the A-frames are square lashings, even though the spars cross at less than 90˚ angle.

Schematic of A-frame alignment

Double A-frame. When you have four A-frames, you can lash two of them together to form a double A-frame. (see figure 140). Lay one A-frame on the ground and then put another on top of it so that the bottom ledgers overlap one-half their length (approximately 3 feet). The first step in lashing the A-frames together is to go up where the two legs cross (the X formed by one leg from each A-frame). Then with a good tight square lashing, lash the two legs together.

Note: The point where these two legs are lashed together is where the foot rope will rest. You can adjust the overlap of the two A-frames to adjust how high the foot rope will be off the ground. Also note where the tops of the A-frames are, because this is where the hand ropes will be. To complete the double A-frame, stand it up so the butt ends of all four legs rest solidly on level ground. Lash the two bottom ledgers together where they overlap with three strop lashings. Now repeat the entire process to build the second double A-frame.

Laying out the distance between A-frames and anchors

Site preparation. Before you can erect the double A-frames, you need to prepare the site. Begin by stretching a length of binder twine along the center line of where the monkey bridge is to be built.  Working from the center, measure 10 feet toward each end to mark where the A-frames are to be placed. They should be 20 feet apart. Then mark out another 10′ from each A-frame to where the anchors are to be built.

Note: These dimensions are for building a bridge with a 20-foot span. This is the maximum span for a bridge using a 50-foot rope. The extra 30 feet of rope is needed to have 15 feet of rope at each end for the proper distance from the A-frames to the anchors (10 feet) and for the knots at the anchors (5 feet).

Build the anchors. The foot rope will be attached to anchors at both ends. Before erecting the double A-frames, build a 3-2-1 anchor, or a log and stake anchor, 10 feet from where the A-frames will be erected (see figure 141).

Rope grommet. After the anchors are built, attach a rope grommet with a ring or shackle in it. (You can make the rope grommet with a 10-foot length of 1/2-inch diameter polypropylene rope. Tie the ends together using a carrick bend, and permanently secure the ends with some strong twine).

Position the A-frames. Prepare to erect the monkey bridge by moving the A-frames into position no more than 20 feet apart. Lay them down on the binder twine that marks the center line of the bridge.

Hand and foot ropes. Now you can prepare the foot and hand ropes for the monkey bridge. Lay the foot rope in a straight line off to the side of where the A-frames are laying. Then lay the two hand ropes on the ground next to each other so they’re parallel to the foot rope and 42 inches away.

Stringer ropes. Now you can add the stringer ropes that will go from the foot rope to the hand ropes. Start by tying the center of an 8-foot long stringer rope (use 1/4-inch manila rope) at the center of the foot rope, using a clove hitch. The stringer rope is tied around the foot rope so that both ends are 4 feet long. Add two more stringer ropes on both sides of the center stringer rope (so there are five stringer ropes in all), tying them about 4 feet apart. Tie one end of each stringer rope to one of the hand ropes, again using a clove hitch. Then do the same with the other ends of the stringer ropes, attaching them to the other hand rope.

Assemble the bridge. You’re just about ready to assemble the bridge. First place a piece of heavy canvas (called a “saddle”) in the V formed by both double A-frames. This will protect the foot rope and allow it to slide a little in the V without interfering with the lashing rope.

Fig142
Schematic of foot, hand ropes and anchors

Now get the crew together to erect the bridge. You will need a safety officer to watch for any problems that might occur, and a signal caller to tell the crew members what to do. You will need two Scouts to lift and hold each double A-frame in place, two more Scouts to lift the foot rope into the V of the double A-frames, and two more Scouts to lift the two hand ropes into place at the tops of the A-frames. Lift everything into place. Then, holding the A-frames steady, temporarily tie the hand and foot ropes into the rings of the grommets using a roundturn and two half hitches (see figure 142).

Tighten the foot rope. Now you can put a strain on the foot rope. It’s not necessary to use block and tackle since this will put too much strain on the lashings, anchors, and the foot rope itself when there is a load on the bridge.* Whatever strain three or four Scouts can put on the foot rope by pulling it by hand will be enough. As soon as the bridge is used a few times, there will be a sag in the rope. This is fine because it means that you are working with reduced strain on the foot rope as a safety measure.

Tighten the hand ropes. Next, tie the hand ropes to the top ends of the A-frames. First, loosen one end at a time from the anchors. Then, use a clove hitch to tie the hand rope to the top end of the leg of the double A-frame. As you’re tying these clove hitches, adjust the strain on the sections of the hand ropes between the double A-frames to match the sag of the foot rope. Also, adjust the length of the stringer ropes so there is even strain between the foot rope and both hand ropes. After the hand ropes are tied to the tops of the A-frames, move down and retie the ends of the hand ropes to the rings in the grommets using a roundturn and two half hitches.

Final testing. With caution, one crew member can get on the bridge as all lashings, anchors, and knots are observed by the safety officer and all other crew members. Make adjustments as required. Then secure the running ends of the hand ropes and foot rope with a piece of cord. Safe operation calls for only one Scout to be on the foot rope of the monkey bridge at a time.

LIST OF MATERIALS FOR DOUBLE A-FRAME MONKEY BRIDGE

  • eight 4-inch x 8-foot A-frame legs
  • four 3-inch x 6-foot ledgers
  • fourteen 1/4-inch x 15-foot lashing ropes for Square Lashings
  • one 1/2-inch or 3/4-inch x 50-foot rope
  • two 1/2-inch x 50-foot hand ropes
  • five 1/4-inch x 8-foot stringer ropes
  • six 1/4-inch x 10-foot lashing ropes for Strop Lashings
  • six pioneering stakes for each 3-2-1 anchor
  • eight pioneering stakes for each log-and-stake anchor
  • one 5-inch x 4-foot spar for log-and-stake anchor
  • two 1/2-inch x 10-foot polypropylene ropes for rope grommets
  • two pieces of scrap canvas for foot rope saddle
  • binder twine for anchor tieback straps

* It has been found that a rope tackle in the foot rope at each end (not a block and tackle) tightened by one Scout is an excellent procedure to maintain the optimum foot rope tension, and an easy-to-use remedy for too much sagging due to repeated, heavy use and over stretching. There are other configurations used to initially tighten and keep the hand and foot ropes at the optimum tension during use, depending on the weight the bridge must withstand and the amount of traffic it will bear.

More Photos

2013 Jamboree Monkey Bridge Modified A-Frame Construction Photo Illustration

Single Pull Rope Tackle Monkey Bridge Configuration

PDF FILE  for: Double A-Frame Monkey Bridge

Scouting Magazine Article