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ScoutEngineering

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Getting startedPioneering or Scout engineering refers tothe work of military engineers who wentahead of the army on foot, to buildbridges, roads and to generally preparethe way.They got there first, often in thewilderness, and had to make do withwhat they could find, or carry. With axesand ropes they worked wonders andcreated many functional structures.In Scouting we carry on this tradition as itprovides Patrols with a challenge and anopportunity to develop as a team andachieve something worthwhile.Before building it is necessary to have anunderstanding of the skills involved aswell as enthusiam. Firstly, it isnecessary to know how to tie therequired knots and lashings, secondly,you must have spars or poles fromwhich to build your project. The nextconsideration is ropes and pulleys to

bridge and secure your project and lastlysome know how and loads of commonsense.Each project should be approached in alogical way:-

What are we trying to doWhat equipment do we haveWhat is the best way to use thisequipmentDesigning the projectPlanning the steps to complete theprojectTesting and safetyDismantling the project

Every project should be approached in thisway. The designs suggested are tried andtested however you rarely find a level riverbed or trees in the right places for ropebridges etc. so each of the basic designssuggested will have to be modified to suit theconditions you encounter.

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BasicStructuresAll pioneering structure are createdusing a number of basic forms -the A frame, the A frame with doublebar, the sheer legs, the square trestle and the rectangular trestle.All of these basic structures arestable if constructed properly and will notmove out of shape.Once the basic shapes are constructed onthe ground they are combined perhaps with anumber of linking spars to provide a tower,bridge or similar structure. As a general ruleit is better to build a big structure from anumber of smaller and reasonably lightframes rather than try to lift heavy frames orpoles.

LashingsExperence would suggest thatthe best lashing to use in theconstruction of the projects isnot the traditional squarelashing but rather theNorwegian lashing which iseasier and quicker to tie thanthe traditional lashing.With the Norwegian lashingthe sisal or lashing rope ishalved and you are constantlypulling the strain againstyourself which makes it easierto tighten and manage theconstruction of the lashing plusyou finish it off with a reef knotor granny knot which ever iseasiest. Once you master thetechnique it can be adapted tothe other lashings - Tripod,Diagonal, Sheer.

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RopesRopes come in many types and sizes and to simplifymatters you should use the following as a guide.

75mm rope (25 mm diameter) or larger, certainly nosmaller than 75mm, should be used whenever it is intended to holdweight such as in the case of a monkey bridge - foot and hand rails,aerial runways, and commando rope bridges.

50 mm rope (16 mm diameter) should be used for ‘reeving’ up pulleysand anchors and for rope ladders.

25mm rope (8mm diametere) should be used for guy ropes in general,on large structures this size would need to be increased.

Quick reference - the size of a broom handle is approx.25 mm diameter.

Quick reference - the size of a man’s thumbr is approx.16mm-18mm diameter

Quick reference - the size of a index finger what is known assash cord or heavy cloths line.

Rope lenghts will vary according to howthey are purchased, 25 metre lenghts willnormally cover most projects as thedistance between sheer legs or ropebridges should not exceed 15 metres toavoid ‘flipover’. Flipover occurs when theslack in the rope is such that it acts muchlike a skipping rope, when pressure isapplied to the middle of the rope itbecomes unstable and sways resulting inthrowing off the ‘rope crosser’ orentangling them in the ropes, which isextremely dangerous.As most of the ropes used in pioneeringstructures require an element of friction toprovide maximum efficiency, hawser laid

ropes of natural fibre such as sisal or hempare preferred, but they are more expensiveand need care and attention as the fibres canrot and deteriorate if not dried carefully.Synthetic ropes are cheap but require extracare particularly when fixing the ropes totrees and poles. The ropes are generallysmoother than hemp or sisal ropes and theknots have a tendency to slip underpressure. To ensure safety and preventslippage you should secure all knots withextra hitches.

Ropes below this sizeshould be used for

lashings only

Simple wooden ropesize guage

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Coiling a Rope

When coiling a heavy hawser it is best tocoil it in large loops on the ground. Passingthe hawser through your legs will aid thisprocess and prevent tangling. The coil isecured using short sisal ties

In order to protect a rope from damage and toaid in transporting it, you need to be able tocoil a rope properly. This can be done in anumber of ways as shown. When coiling letthe rope fall into natural loops. In order for thisto happen it will be necessary to flick andturn the rope. Once completed the coil issecured by a whipping type knot or via aloop knot.

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PulleysMost pioneering projects can becompleted using 2 pulleys - a singleblock and a double block. However, it isbest to aim for 2 single blocks and 2double blocks and perhaps a number ofsmall blocks - the ones used forclothsline and sailing. This will allow youto complete most projects you willventure to undertake.

MousingIf you are in possession of a hooked block it cannot beused by the hook alone. All hooked blocks need to be‘moused’. This is done using sisal which is boundaround the ‘bill’ and back of the hook as shown.Mousing is not 100% effective so it should be checkedat regular intervals when in use on a structure.

The size of your blocks will need to be;-150mm for 50mm rope230mm for 75mm rope

By employing single and doublepulleys different pull ratios can beachieved

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Fix line to pulley using a roundturn and two half hitches. It is alsoa good idea to whip the free end ofthe line to prevent slippage. Youcan also use a stopper knot if youwish to do the same job.

Catspaw knotThis knot is used to connect aline to a hooked pully asshown.

If you are using aclosed eye pulley itmaybe necessary touse a D ring shackleto allow you to attacha heavy line.

Reeving a simplesingle and doublepulley system

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AnchorageIf at all possible you should anchor yourropes to a fixed object such as a ‘big’ treeor rock. However, they are rarelyavailable in the right places so we haveto create our own anchors. There are twopossibilities the 3-2-1 picket and the picketand log anchor. Both are illustrated below,in each case the pickets should be atleast 160cms long and put in position witha sledge hammer or large mallet. If theground is soft they may need to belonger. The pickets should be set in theground at 60 degrees and the bindingsbetween pickets should always run fromthe top of one picket to the bottom of theother.

As a rule of thumbPickets should be positioned in theground approx. 3 times the height fromwhich the main rope leaves the structure.i.e. if the main rope passes over thesheer legs at 3 metres above the groundthen the pickets should be set in theground 9 meters from the base of thesheer legs.It would be normal practice to fix the ropeto a log and picket anchor and fix thepulley assembly to a 3-2-1 picket anchor.

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Fixed anchorsWith fixed anchors, such as trees, you needto create a loop of rope on which to fixpulleys. This is done by wrapping a ropearound a tree a number of times as shown.The collective strenght of the loops of ropemust exceed the strength of the rope beingstrained otherwise the loops are the weakestpart of the structure. It is therefore suggestedthat 25mm rope is used for this job and iswound around the tree at least 4 times.

Protection of treesIf you are fixing a rope or spar you shouldbe careful not to damage the bark. This canbe done by using some sacking or oldcanvas to protect the bark from friction.It may also be necessary to use sacking orpadding on a structure if the rope will besubject to excessive friction, particularly inthe case of a monkey bridge. this isparticularly important when using syntheticropes as they are prone to melt if in a frictionsituation or if two ropes are rubbing off eachother.

3-2-1 picketDeadmans Anchor

Log and picket anchor

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Getting upA problem that can be encountered whenpioneering is getting up a tree to secureropes and pulleys to branches

Prusik KnotThe prusik knot is a friction knot whichallows it to slid on a rope when free of aload but will grip the rope when understrain. To climb a rope you will need threeprusik loops fixed onto the main rope - 2for the feet and 1 as an underarm loop.The rope is climbed by sliding the knots,one at a time, so that it is possible to ’stepup’ the rope using the foot loops. Withpractice a rhythm can be developedwhich will allow you to climb the ropewith ease.

Rope laddersRope ladders are constructed using theMarline hitch or Clove hitch.

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How much equipmentdo you needIn order to undertake all of the projectsshown in this chapter you need to have thefollowing minimum quanties of equipment inyour store. The quantity listed is to completeone project at a time.Most Units have a stock of spars andpulleys so it is only necessary to borrowthem from the Unit quartermaster. Apart fromthe large spars you will also need a numberof small poles for platforms, rungs for laddersand handrails.

Rope ladderIt is better to have a permanent rope laddermade and in your store rather than makingone each time it is required.

RopesYou will need a main hawser, 75mm rope,for footrails and for use whenever a rope isexpected to hold weight. These ropes aresold in set lengths and you should not cut it.50mm ropes and smaller will probably beprovided in various lengths by thequartermaster and again you should not cutthese.Lashing ropes will also be required, againyour quartermaster will probably supplythese already cut into working lengths.

Pulleys

You will need a minimum of 1 double blockeither 150mm or 230mm depending on thesize of the rope to be used (normally150mm). Depending on the design andlocation of your project you may require twoof each to cover all situations.

These large blocks can be supplementedwith a number of smaller pulleys which areuseful for hauling and small lifting devices.

A rule of thumb for lashingropes

1 metre of lashing rope should be usedfor every 25mm of thickness of the sparsto be secured together. i.e. two 75mm spars require 6 meters oflashing rope.

Equipment list4 No. 5 metre spars6 No. 4 metre spars10 No. 3 metre spars10 No. 2.5 metre spars8 No. 2 metre spars8 No. 1.5 metre spars

Selection of poles for pickets and smallspars for platforms, rungs for laddersand handrails

1 No. Rope ladder1 No. 75mm rope - main hawser2 No. 50mm rope - long lengths

for handrails50mm reeving rope for pulleys25mm rope for guy lines (15 metrelenghts)Lashing rope and sisal of variouslengths

Pulleys2 single (150mm or 230mm)2 double (150mm or 230mm)5 small pulleys (clothes lines or sailingtype)

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Getting overOne of the problems encountered whenconstructing a bridge is how to getmembers of a Patrol or construction crewto the other side of the river or stream sothat the bridge can be completed on bothbanks of the waterway. Derricksare a simple method ofovercoming this problem andare illustrated below.

An double bar A frame is constructed and amember of the Patrol sits on the frame. Aforked pole is used to prop the frame andnudge it forward.

Simple DerrickThe simple derrick is constructed using twospars loosely tied together. a loop of rope isattached to both spars so that it is possiblefor the ‘traveller’ to balance and maneuvourthe spar over the waterway. The rope shouldbe attached on each pole using a round turnand two half hitches. Guys are fixed to thetop of the derrick. The derrick is balanced byPatrol members using guys until the firstScout is across then the guy rope is passedover which will allow the structure to besupported more easily.

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A double A frame is constructed. first Scoutacross stands on the frame and a forked poleis used to push frame over. The rest of thePatrol manning the guy ropes, control thebalance and descent of the frame. The Scouton board jumps to the bank.

This swinging derrick is slightly morecomplicated to construct. A ‘slim’ double A-Frame is constructed and pulleys rigged asshown. The ‘traveller’ pulls on the pulleyrope to raise themselves up. Some of thePatrol haul the A-frame into position and theother members swing the frame over thevoid.

Wooden seat is attachedto ropes using ascaffolding hitch

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TowersTripod TowerThis tower is reasonably easy to construct.All the lashings are square except the tripodlashing on the main spars.

Equipment required3 No. 5 metre spars3 No. 3 metre spars3 No. 2 metre spars3 No. 1.5 metre spars3 No. 1 metre sparsSmall poles or planks for platformLashing ropesGuysRope ladderSpade to dig butt holes for tower

How to buildPlace a tripod lashing three - quarters upthe 5 metre spars.Lift the spars straight up and create tripodshape.Fix 3 metre braces to the bottom of thetripod using square lashings.Drop the tripod to the ground and placetop braces on tripod allowing them to jutout of each side.Build the rest of the platform structure.You can also build the top structure asone piece and place on top of the tripod.Fix guy ropes and rope ladder and raiseinto position.You should dig a number of small holesfor the butts of the spars to fit into.Secure guys and test rope ladder andplatform before general use.

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Hour Glass TowerThis tower is slightly more complex than thetripod tower however the principle ofconstruction is the same. The tower isconstructed by using two tripods, oneinverted on top of the other. It is alsonecessary to brace the two tripods to preventthe top tripod swaying.

Equipment required3 No. 4 metre spars6 No. 2.5 metre spars3 no. 1.5 metre sparsSmall poles or planks for platformLashing ropesGuy ropesSmall spade for digging holes to butt mainspars.

How to buildCreate a tripod with the 3 No. 4 metrespars.Raise the tripod and fix braces (2.5metres)Drop tripod to ground.Make a second tripod using 2.5 metrespars.The legs of the tripod should be‘threaded’ through the base tripod.The spars are then lashed in place usingsquare lashings.The top braces (2 metre spars) are fixedonto top tripod and platform base iscreated (1.5 metre spars). Fix smallpoles or planks to form platform.A loose binding is fixed at the top of thelower tripod and base of top tripod toprevent swaying. This will need to betighten when tower is raise to straightentower.

Rope ladder and guys should be fixed toplatform before raising the tower.Place butts of tower in small holes dug atbase.Fix all guys . Test structure beforegeneral use.

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Place a tripod lashing on 4 sets ofspars as shown in diagram. thecentre pole being 2.5 metres inlength. the two ouside spars being 3metres in length.Stand up tripod ‘sets’ and spread outlegs so that the 3 metre spars act asbraces, the centre spar as the cornersupport of the tower.Move the sets together usingtournique lashings at the bottom anddiagonal lashings as the bracescross.

Place 2.5 metre spars on top to bracetop section together.Place planks on top to provide platformsif it is to be used as a single tower.

Ten Minute TowerIn theory and with practice and the use oftournique lashings it is possible to erectthis tower in ten minutes. This structureprovides an ideal challengefor a Patrol at a Troop or Patrolmeeting, however, the tower tendsto be used to create more complexbridges using a number of towers tobridge a wide river or lake.Tripod, diagonal, square andtournique lashings are required to hold the structure together. Thestructure is self standing and can be liftedor carried into position.

Equipment required8 No. 3 metre spars8 No. 2.5 metre sparsPlanks for platform baseLashing ropesSmall poles for tournique lashings

How to build

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Tournique lashingThe tournique lashing is made using a loop ofrope and a small pole. The loop is passedaround the spars to be lashed and a smallpole inserted in the loop. This is twisted untilthe binding is tight. The small pole is thensecured to the nearest spar with sisal toprevent it unraveling.

Turnique lashing(starting thelashing)

Turnique lashing(tightening the lashing)

Figure of Eight lashing

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Bridges

A 3-2-1 picket anchor should be placedin a straight line to the ‘foot rope’ on eachside of the river bank. If only one set ofpulleys is available then a log and picketanchor is placed on one bank and a 3-2-1 picket anchor on the other to whichyour pulleys are attached.Hand rails are attached using clovehitches and are carried down to theground like guys.Securing ropes are tied between thehandrails and footrope using clovehitches.Test structure before using.Pulleys will need to be checked atregular intervals to take up slackening ofropes with use.

How to buildAssuming you have access to bothbanks, construct two sheer legs withthe crossing of the spars being a littleabove half way. The top portion ofthe spar should allow you to positionthe handrails at about shoulderheight. The distance between the tipsof the spars should be 1 metre apart.The sheer legs are then raised intoposition and the base of the sparsbutted into the ground and guyed intoposition.Old canvas or sacking should beplaced in the diagonal to reducefriction and wear on main footrope.The main rope (75mm) is passedover the sheer legs and the rope

Monkey BridgeThe monkey bridge is constructed using two sheer legs and bridged witha hawser and handrails secured using pickets. this an easy structure tobuild as most of the bridge is constructed using rope.

alined and handstrained so that theposition of anchorscan be determined.

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Commando bridge

Single log bridges

Suspension bridge

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Trestle BridgeThe trestle can be used as abasic building block for a wholerange of bridges. The bridge illustrated isthe locking trestle bridge which can eitherhave a see-saw bridging platform or afixed ramp on each side.

Equipment required2 No. 6 metre spars8 No. 4 metre spars2 No. 3 metre spars3 No. 2.5 metre sparsSpars for handrail supports and rungs forbridgeLashing ropesHandrail ropes

How to buildConstruct two trestles. It will benecessary to construct these accordingto the depth of the river and river bank.These trestles are placed opposite eachother on the banks of the river andallowed to fall together.A ladder type construction is createdusing the 6 metre spars and small polesand handrail supports.A 2.5 metre spar is placed between thediagonal created by the joined trestles.This is not fixed as it is a rolling pivot forthe ladder structure.The ladder is fixed to this rolling spar.A large log placed on each bank willprotect the bank from damage causedby the see-saw action of the bridge.

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Draw bridgeThe draw bridge is similar in construction tothe trestle bridge. You need a trestle frame, aladder structure - drawbridge- some tackleand picket anchor and a large log.

How to buildConstruct the trestle frame, bottombrace position will be determined byheight of log.Make a ladder structure using 6 metrespars and small poles as rungs.Fix 4 metre braces from trestle frame toladder and fix handrails. the handrailscan be of rope or spars if you prefer.Place 3-2-1 picket anchor in the groundand rig up a pulley to it.

Equipment required2 No. 6 metre spars6 No. 4 metre spars1 No. 3 metre spar1 No. 2.5 metre sparSmall poles for ladderA large logPicketsPulley and 50mm ropeLashing ropes

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Otherchallenges

Friction bridgeNo lashings are used in its constructionyou rely rather on the friction and tensionof each log in the bridge to hold thestructure together

Outback Bridge

Square tower

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Abington spring bridge

See-saw Bridge

Handrail detail

Stilt Tower

Simple ‘A frame design’ Bridge

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LeveringandliftingDid you ever wonder how ancientpeoples such as the Egyptians and theDruids managed to move large stones toform the pyramids or Newgrange - theused levers. This tried and proven

method of shifting heavy loads should beused by your Patrol but to conserve energyand prevent injury.When levers are being used for movinglogs, or prising out boulders, care must betaken that the lever is strong enough towithstand the strain that is being placed on it.If you are using a lever to lift and object, lift itonly a small distance at a time and place aroller or solid block under the object as youlift it. This will enable you to reposition thelevel after each lift. Work as a team tocomplete these type of tasks as accidentscan happen if lifting is not undertaken withcare.

Lift large poles using a team of people anduse guy ropes to control the lift. It maybenecessary to construct an A frame to aidlifting.

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Bamboo andelastic bands

Simple and elaborate structures can be builtusing bamboo canes and elastic bands. Thesecret is to construct small pyramid shapeswhich are strong and stable. These pyramidsare then locked together to make morecomplex structures. It is important howeverthat you maintain the pyramid shape in yourdesign as it adds stability to the final project.It may also be necessary to peg down thestructure to the ground in case of windyconditions.

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Rope weaveThere are few pioneering projects whichcan be described as ‘aestheticallybeautiful’. The rope weave structure hasvery little value and the finished productis eye-catching, graceful and looks farmore complicated than it really is.

SitingThe transparent nature of the rope weavemeans that it will blend in with anycountryside and would not look out ofplace on top of a hill.

DiggingGuy lines of any sort will ruin the effect ofany rope weave project which meansthat any upright poles must be dug firmlyinto the ground.

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StaplesYou will need strong wire staples tocomplete the rope weave. There shouldbe the same number of staples on eachspar. The distance between the staplesis normally 100mm - 150mm aparthowever it is possible to vary thedistance on both spars to create neweffects - so experiment!

Stringing upThe poles should be loosely strung upon the ground, using a continuous lengthof string or coloured bailing twine, whichcan be tightened once the poles arefirmly in place.

ErectionErecting the structure is best done usingsheer legs and temporary guys until thespars are firmly in the gound.

TighteningTightening will probably need to be doneseveral times, depending on theweather. A ‘saggy’ weave does not lookwell.

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Peg and dowel

Peg and dowel is a traditional techniqueused by craftspersons in the creation ofrustic and tradition furniture and fencing.The technique involves the paring ofpoles and stakes and the drilling of holesto accept the pared poles. A scotch eyedauger is used for drilling this needs to beabout 30mm diameter.Many designs are possible and any itemof furniture normally make on camp canbe created using the peg and dowelmethod.

Of course you could also use a hammer anda few nails but where is the skill in that. Pegand dowel is a secure method of makingcamp structures and they will last the rigoursof camp. You may want to consider makinga set of rustic furniture for your den to give itthat Scouty feel. It is also possible to makelarger projects such as camp gates and sosimple bridges.

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Tools required:-Scotch eye auger and draw knife

The ‘horse’ allows the paring ofstakes to be done with easyand safety. Pressure is appliedto the foot pole which in turnapplies tension to the rope tieand secures the working staketo the horse.

Any camp furniture that is created usinglashings can also be made using the peg anddowel technique.

Joints are secured using a ‘hidden wedge’- ahole is bored to accept the pared point. Asmall wedge is placed in the peg and as thejoint is knocked together the wedge seals thejoint. A dowel can also be used which isdriven down through the stakes as shown.

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Fun projects

The first step in building a tree house orsleeping platform is to find a suitable treeor collection of trees growing in a group.Look for a tree that has branches whichare strong and suitably spread apart sothat a platform can be constructed. Gathertogether all the equipment you will require- tools, timber, pallets or plywoodsheeting, ropes and safety equipment.The design of your tree house will bedetermined by the shape of the tree youselect, as a result many designs arepossible. Start off by making a simplesketch taking into account the branchesavailable in particular the ‘branch elbows’where the branch attaches itself to themain trunk.Use pulleys and ropes to lift logs up to

the platform area. This should be donecarefully so as to avoid any unnecessaryaccidents. The base of the platform can beconstructed using spars to get a rustic feel oryou can also use a number of pallets or asheet of shuttering plywood. Be prepared tocut any sheeting to shape.Anyone working up the tree should beprotected by means of a safety belt and fixedloops on to the main tree. You should also becareful when using tools on the platform sothat those on the ground are not injured fromitems falling on their heads.Once the platform is constructed you canthen consider building the rest of thestructure.

Tree houses and raised sleepingplatforms

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Bodgers LatheThe Bodger lathe is a fun project to build. Thelathe is created by first placing a large stake inthe ground and attaching a springy sapling to it.This is the driving force behind the lathe. Astring or light rope is attached to the top of thesapling and in turn is wound around the woodto be turned and on to a foot pedal device. Thefoot pedal can either be a piece of flat timber ora forked stick that is pivoted so it can movefreely.Two other stakes are required which should bebored on each side to accept the wood to beworked. The working piece should be able tomove freely and spin backwards and forwardswhen the foot pedal is operated.In order to work up the spindle you will alsorequire a set of sharp chisels.

Camp ballista

You can also use an tyre tube to create thetension on the ballista.

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Camp Gateways