56m suspension bridge at Manjedal Activity Centre, Western Australia

Greg from West Australian Scout Pioneering wrote in with photos and a description of the awesome bridge, supported by A frames on each end and a raft in the centre. Here's Gregs description:

Photo courtesy Greg Barbera

Project : Build a Rope bridge for the West Australian Cub Scout event – Enduro 

Location: Manjedal Activities Centre (M.A.C) – Lake Jones 

Depth: Varies from 4 meters to 15 meters Span: 56 m (40m over water) 

Water Temp: Very cold 

Weather: everything except snow 

Duration: 16 hrs to build

Photos courtesy Greg Barbera

To help celebrate the 100th Anniversary of Cubs, the Organizing team decided to go with a “Back to the Future” theme. They also want to surprise the cubs by having an activity based around the traditional methods of pioneering that have been with the movement for over 100yrs. The West Australian Scout Pioneering Crew (WASP) were asked to build a bridge across Lake Jones that would be sturdy enough to withstand a very large number of Cubs and Leaders using it.

Over the two days of Enduro approximately 800 Cubs and a small number of leaders made the crossing. To ensure the build met the requirements of pioneering in Australia, the walk rope was set at a height of 1.8m from the ground so that helmet & harness would not be required (anything over 2m). This meant that we had to install some form of support in the middle of the arc to keep the ropes & cubs out of the water. Several suggestions where made of a tower, but owing to the erratic shape of the bottom of the lake there would be no guarantee that a level section could be found. It was decided that a pontoon would work providing it could be securely moored and be able to support the bridge as it pass over it. It was decided that a 4m x 4 m pontoon made out 100mm dia. pine logs with 4 x 200ltr blue plastic drums and 6 x 140ltr white drums would both support it and stabilize the middle section. In addition 2 vertical poles where fitted so the bridge ropes could be attached to the pontoon using Carabiners, this would still allow the ropes to be tensioned without moving the pontoon from its moored position. 

We also fitted an arrival and departure deck which only covered the area under the bridge, a walkway was also fitted for a leader to use to assist those passing through the middle section. On the trial build of the pontoon we fitted guy ropes to the vertical posts but found that caused problems and a trip hazard for the leader, so this time we used 3 spars on each vertical and lashed them in place, to reduce the amount of rope required we made the first lashing a figure 8 and pulled the side poles out to create the angle brace. Then fitted one on the outside and lashed a horizontal spar in place so the walk rope could also be clipped onto the pontoon. For this span we fitted each line with 2:2 rope block combination and used the pontoon as a means to keep the lines tensioned as the combined weight totalled approx 350 kg. The main ropes where 20mm dia. sisal and to assist the hand rails to support the walk rope we fitted short lengths of rope which we refer to as stringers. Normally when we fit pulleys on to the main ropes to take up the tension, we used the prussic loop to attach the block, for this one we used the “Dog & Tail hitch”. This hitch does the job well and is easier to move when it is not under load. 

On the shore we used “A” frame assemblies that are self supported by guy ropes and thus allowed the main ropes to be tensioned freely. Carabiners were also tied to the frames to support the hand lines. To stop the main line travelling along the horizontal bar, we used a short length or rope and tied a clove hitch on both sides. Normally we would use a log & picket anchorage for our rope bridges, but in this case the ground on both sides was too soft to get a good footing. On one side the soil was too moist and on the other side there was a very large ant hill, which meant we had to contend with hollow ground owing to the nest. We therefore bound the trees with hessian to reduce any damage to them. 

To reduce the risk of the Cubs endangering themselves if they fell off, each person making the crossing was required to wear a life jacket and we had a rescue craft on standby (canoe). Out of the 800 cubs only 2 ended up in the water and 7 were rescued by the safety vessel as they held onto the hand rails.

Suspension Bridge from Feb 1937 Scouter magazine

I found this suspension bridge article written by L.C. Sands in the February 1937 Scouter magazine:

No special credit is claimed for having succeeded in building the bridge described here, as it involves a principle in common use, but as the writer has not seen anything similar described in any of the books on pioneering, he considers that other Scouters might possibly like to try it out, and doubtless improve upon it. Its chief advantages are that it needs only simple materials, is easy to construct, and is one which could be crossed with ease by many people who might hesitate to venture on a monkey bridge. Any measurements stated here may be altered to suit local conditions.

Two Towers were constructed of four spars about 9 ft. long, with 1 1/2–2 in. butts, and seven Scout staves 5 ft-long. First the side trestles were made by lashing two spars together as near the top as possible with a sheer lashing, and then the ledger was put on with square lashings about oft-from the bottom of the spars. These two trestles were then connected together to form the tower by lashing a strong pole across the top in the V’s made by each pair of spars, and by lashing poles adjacent to or slightly above the ledgers of the original treetles. The base of the finished tower was about 4 ft. square. About 2 ft. from the ground further poles were lashed to both back and front of the tower: the one (A in the diagram) nearest the bridge proper bore the two hawsers of the roadway, while both bore the planking.

The Roadway was made with two 2 in. ropes to which were attached twelve Scout staves at intervals of about 1 yd., by means of lever hitches a few inches from the ends of the staves. This method is probably not the best for strength, but it is quick, although about 1 ft. of the rope is used up in making each lever hitch. When this is swung into position, the ropes at one end should pass over the front pole (A) on the tower, under the back one (B), and be made fast to pickets or some convenient tree if available. The other ends should be similarly secured, but if possible block and tackle should be used to tighten them at one end, as was used in this case.

Suspension lines were made from 1 in. cord throughout, twelve in all three for each side of each half of the bridge. These lines were attached to the pole forming the road-bearers of the bridge, and to passed over the top pole of their respective towers to pickets or suitable trees. In the case of the lines attached to the two centre poles (E and F.)loops should be made in the cords about 2 feet from the ends fastened to the roadbearers. The two loops in these two lines from E and F (see diagram) were then drawn towards one another by another cord until the angles between the roadway and the portions of the cords below the loops were almost right angles, and then made fast. This other cord was then continued in either direction, taking a turn round each of the suspension lines in passing to the towers, to form a handrail. The reason for so dealing with the middle suspension cords was to increase the angle between the suspension lines and the roadway, so as to get a better suspension of the centre part of the bridge This proved the most satisfactory of several methods tried.

The other cords from C. D. G. and H go straight from these points over the top poles of the towers to their respective pickets. These suspension cords should all be fastened on to the roadbearers at D, E, F, G and H before the suspension part of the bridge is swung into position across the gap to be bridged. All that then remains to be done is to pass the cords over the top bars of the towers and fasten to the pickets. Before use the suspension cords should be adjusted so that the centre of the bridge is slightly higher the the ends. This method of suspension was found to be the most satisfactory and easiest to make as any particular cord can be readily tightened up. Of course extra strength would be gained by adding similar cords to some - the other road-bearers, e.g., those between C-10, and G. H.

To complete the bridge some form of planking should be laid across the road-bearers and lashed to them. In this case, some fifteen inches (in width) of planking put on for the whole length, and this in itself was a considerable weight. The length of the actual bridge between the towers was 38 ft.

This bridge proved very satisfactory in practice. After it had been used a number of times the drop in the centre, while an average-sized adult was standing on it in the middle, was only 9 in, and it may be added that the writer rode his bicycle across it.

Obstacle Course by Carpe Diem Scout group in Arendonk, Belgium

Scouts Carpe Diem Arendonk in Belgium built this obstacle course structure outside, around and over their Scout hall. This timelapse shows the construction process:

While these photos from their Facebook page show the structure in use:

Pioneering as community service: permanent bridge by 1st Blairgowrie

Today is Nelson Mandela's birthday. Over the last few years, South Africans have been encouraged to spend 67 minutes of the day serving the community- signifying the 67 years Mandela gave in service to the country. This post looks at a permanent pioneering project that serves the community.

I was running through Delta Park, a large municipal park near my office, a few weeks ago when I noticed a Scouts South Africa notice pinned to the foundations of a bridge.

1st Blairgowrie Scout Group are responsible for this project, which is being led by James, a Springbok Scout candidate. The bridge is being built to offer an additional crossing point for the stream that flows in this part of the park, making it safer for the cyclists and pedestrians using the extensive trail network: the park is very well used, especially on a Saturday morning. Work has progressed in the last few weeks, and as you can see, only the decking and access ramps remain to be completed.

A few things are noteworthy:

• the materials for the project are being funded by donations from the local community, who are active in assisting with improvements to this park.
• the poles being used are stripped and treated gum poles, from local eucalyptus plantations. These are the cheapest and most widely available pioneering poles in South Africa.
• bolts have been used instead of rope to make this structure more permanent. Is it still pioneering? I think so.
• A final piece of trivia that links this bridge to Baden-Powell's friend, Rudyard Kipling, who wrote the Jungle Book: the stream it crosses is a tributary of the 'great grey-green greasy Limpopo' from the Just So stories.

UPDATE: Further down the same river, 1st Bryanston Scouts have just opened a bridge for pedestrians and cyclists- photos courtesy Johannesburg Parks.

Haymaker's bridge

The Haymaker's bridge is a classic patrol challenge, and with the weather warming up in the Northern  Hemisphere, now is a good time to try out this activity where at least one person is guaranteed to get wet.

In principle this is simple- the bridge is supported by the mast, and each person crossing the bridge balances along a pole to the mast, then supports themselves by holding the mast and 'flicks' the pole across to the other side of the stream.

Once everything is in place, this is fairly simple, but the first person crossing the bridge has a bit of a job. This is a good project to present to a patrol as a challenge during a troop meeting or on an incident hike.

Early 20th Century pioneering - Manual of Military Engineering

In Scouting For Boys, B-P refers to the Imperial War Office's 1905 Manual of Military Engineering for more information on Pioneering. 106 years later, that same manual is freely available online, and while some chapters are not really relevant to pioneering (eg. table of charges for hasty demolition of walls), there are some great resources, including some camp cooking techniques.

From knots, to lashings, anchorages, bridges and rafts, this book covers a wide range of pioneering projects, and shows how B-P's military experience influenced the sort of activities he chose for Scouting.

Arrowe Park Bridge by First Benoni Rovers

The Rover Crew of 1st Benoni Sea Scouts, the Puddle Pirates, built this bridge/gateway for the East Rand District BP Sunday Parade at Arrowe Park. It is modelled after the chapel at Arrowe Park, which is also the emblem of the East Rand District.

The Rovers spent one day building the project, which is built over and around an existing steel bridge. The gateway is supported by a series of guylines onto the bridge deck- not quite the cable stayed bridge I was talking about two weeks ago but very similar in appearance.

Congratulatiosn to the Puddle Pirates on building this gateway, the chapel at Arrowe Park is shown in the photograph below for comparison.

Types of pioneered bridge

All bridges can be classified into one of a few categories, based on how the structure supports the load. Pioneered bridges are the same, and most fall into four categories:

1.  Simple or beam bridge: this is the simplest case, a bridge where the deck itself carries the weight of the structure. This bridge built by Culford School Troop is an example, and most drawbridges function this way in the down position.
2. A trussed bridge is a structure where the supports are triangulated members. The double lock trestle bridge is one example.
3. A tied arch bridge uses an arch that hangs above the deck to support the deck. In pioneering, the Banana Bridge uses an arch made from pioneered frames.
4. Suspension bridges use a structure hanging in pure tension to support the load, either as a separate deck like the Abington Spring Bridge, or by walking directly on the tensile members in a monkey bridge.
5. Cable stayed bridges (like the Nelson Mandela Bridge in Johannesburg) use a tower or series of towers that support a deck using straight cables. I'm not aware of any pioneered cabel stayed bridges, but I'd love to be proven wrong.
6. In an arched bridge, an archway forms the deck, or runs under the deck, and supports the load. Ploeg Technieken in Belgium built this bridge supported by arches.

Of these 6 types, types 5 and 6 are pretty rare in pioneering- I can only think of the one arched bridge, and I can't find any cable stayed pioneered bridges. So, before the end of summer (for us down here in the Southern hemisphere) or, while you're waiting for the weather to warm up (for you up there in the Northern hemisphere) , why not give a cable stayed bridge a try?

Update: 1st Hillcrest Scouts Suspension Bridge

Last year I blogged about a suspension bridge across a ravine in Kwa-Zulu Natal by 1st Hillcrest Scouts, built in 1984. At the time I only had the information from the Veld Lore newspaper to go on, but Andrew Friedemann, who was the Scouter who wrote the original article, got in touch with me and provided me with some higher quality, colour photographs. He says that around 30 Scouts worked on this project, and it was completed on the day of his 21st birthday.

Stave bridge

photo by G.W Sutcliffe, from the cover of the April 3, 1952 edition of The Scout. Note the broken stave in front of the last Scout

Cartoon: Tommy the Tenderfoot

For Founder's Day: I came across this postcard in a collection of Scout memorabilia. Drawn by Baden-Powell, this series of cartoons was first published in 1918. More information about the series is available in an article by William Hillcourt.

Suspension bridge by 1st Hillcrest Scout Troop

 From the Winter 1984 edition of 'Veld Lore', the Southern African Zone Scout Newspaper:

A Suspense story... THE BRIDGE!
By Andrew Friedemann, S.M. Outdoor Activities, 1st Hillcrest Scout Troop, Natal/Kwazulu area

6 p.m on Friday 30th March (1984) saw 35 Scouts from 1st Hillcrest leave their Scout Hall for a 4-hour night hike, negotiating two valleys and a cliff-face. to the site of a weekend of hard pioneering.

We were to attempt a record-breaking monkey bridge which would span two cliff faces 57 metres apart, and a river 35 metres below. At 6:30 am on Saturday we got busy with holdfasts and sheerlegs. The 'Deadman' holdfast was 2 metres deep, with a concrete railway sleeper instead of the usual pole.

At 9 a.m, while testing a damp mainline, the first catastrophe hit us- it broke. Then the rain poured down but the boys, with true Scout spirit, insisted that we carry on with the project. Later, two and a half hours behind time, we got the four mainlines tight- double foot rope and two single hand ropes. It is now 1.30 p.m

The long, laborious task of putting the 10mm rope strings along the length of the bridge began. In addition to the usual structure there were bamboo cross-pieces between the handrails, every 4 metres, to keep them equidistant.

At 5.30 p.m, with 10 metres left to complete, we knocked off for a braai and a camp fire. 10.45 p.m. found us tucking up for the night and - as we were roughing it - we slept under the stars, and the rain, with only the trees for shelter. "This is great," said one Scout, "it's the first camp where I don't have to keep clean!"

At 6:30 a.m on Sunday morning, with clear skies and sunshine, we were back on the bridge, and completed by 8 a.m.

Everyone crossing the bridge recieved a Nut Award which consisted of a plastic shoestring with metal nuts on the end, Wood Badge style. You HAD to be nuts to cross our monstrosity, but even our Group Scouter made it.

At 11:30 a.m. we starting dismantling 'The Bridge' and were ready for the trip home by 3 p.m. One parent said to his son: "But it wasn't worth it, for such a short time?" His sone replied: "It wasn't up for long, but WE DID IT!"

Scout-built bridges in urban adventure race

images courtesy www.urbanrun.co.za

The Nelson Mandela Bay Urban Run takes place in September in Port Elizabeth, South Africa. Last year, the Scout groups of Nelson Mandela Bay built two obstacles- a monkey bridge and a tripod-based bridge, pictured above. They have been approached to build obstacles again for the race this year. This is a great way to build awareness for Scouting, making the movement visible to people who are active in the outdoors.

This year, the Scouts are building a pontoon bridge from recycled plastic bottles. I hope to have some photos to show you in September.

Simple Bridge, Culford School Troop, 1952

Pictures and notes from a summer camp, recorded in The Scout Annual, page 53 of the 1953 edition, dated 24 July 1952 (60 years ago last Sunday) 

 "Summer camp is here again- so let's make a bridge!
Senior Scouts of Culford School Troop bridge a stream at their camp site."

Many hands make light work - and yes ! IT HOLDS !

Camel Raft Bridge

The Camel Raft is the simplest steel drum raft, using just two poles and four ropes. This project joins a series of two barrel camel rafts with poles and decks to make a floating bridge.

The first module would have two barrels at each end, and would be anchored to the shore. Each module after that would only need a pair of barrels at one end, and the other end would rest on the barrels of the previous module. This system could also be used to build a floating jetty. If you pre-assemble all of the modules, this bridge could be spanned across the water very quickly.

I've been itching to try this but haven't got around to it yet, if you do, please let me know about it.

Pioneering competition - trestle bridges

This newspaper clipping from the 4th of May 1973 shows single lock trestle bridges built by Scout troops in Benoni, at a competition camp at Arrowe Park.

From the accompanying article:

Benoni District Scouts attended a camp competition last weekend at Arrowe Park, organised by fourth Benoni Rover Crew.
...

Highlight of Sunday morning was a pioneering project which entailed building and erecting a suspension bridge by each troop. Third Benoni was judged builder of the best bridge.
...
Acting District Commissioner Mr Noel Moor complimented the Rovers on a very "successful and enjoyable camp

Simple Friction Lock 'Bridge' - Instructions

I've written about friction lock projects before- like this table and this pole rack. This post a simplified friction locking pioneering bridge.

The purpose of this project is as an 'icebreaker' in a pioneering session - even Scouts who have no knotting experience can build one of these 'bridges', and feel that they have achieved something. A patrol will gain confidence from this exercise that will motivate them to learn lashings during the later parts of the training session.

This project requires 9 Scout staves or similar sized poles (bamboo may be too slippery), and the instructions show a sequence for the construction of the bridge (inspired by my favourite childhood toy, of course). Click on the image to enlarge it, and print the enlarged image. Step 5 is the critical one: your Scouts should pay careful attention to the placement of the two transverse poles, making sure they go over and under the correct poles.

Using only these instructions, all of the patrols in our troop were able to build one of these bridges. The fastest was built in about 2 minutes (admittedly this patrol had built one before) but I would allow 10 minutes for Scouts who have no prior experience. Here is the first patrol finished, with a Scout testing the sturdiness of the structure (please excuse my grainy camera-phone photograph):

Belgian arch bridge

This bridge was built at last year's Belgian Jamboree, by members of Ploeg Technieken, who have featured previously with the cloverleaf lashing. Kim notes that this was built 'only with manpower, no cranes, winching ... just people with hands ;-) '

This is a large and complex project, built from a series of smaller assemblies- see, for example, the 'ladders' that interlock to form the arches in the middle photograph below.

Thanks to Kim for sharing this. More photographs, including construction details and closeups of the model, here.