bridges (16) campsite (25) cartoons (15) centenary (2) discussion (5) experimental (44) gadgets (23) gateways (9) lashings (21) models (9) raft (77) resources (25) sculpture (15) software (22) techniques (37) towers (42) trebuchets (5) treehouses (17) tutorial (9)

May 16, 2016

Kontiki 2016 Roundup and videos

KonTiki 2016 came to a close yesterday morning, after 60mm of unseasonal rain left the campsite waterlogged. The majority of rafts spent the night on the water, and the competition went ahead- congratulations to 1st Morningside who were all the overall winners!

Hennie Hamman, from Arrowe Park, has produced a series of videos summarising the weekend:
Friday night:


I'll be blogging some more about KonTiki once the full results spreadsheets are out, and once the organisers relsease some more photographs- there were a few timelapse cameras running over the weekend, and I'm looking forward to seeing them.

May 14, 2016

KonTiki 2016: Saturday- Rafts and Land activities

Saturday is the busiest day at KonTiki- rafts are completed, and after being checked for sea-worthiness, are launched and begin their competitions on the water. Meanwhile, on land, the Beaver Challenge competition has run for the Cubs and junior Scouts, campsites are being judged, and meals are competition meals are cooked.
Here are some of the rafts preparing for launch. Because of space limitations at the venue, rafts are built three rows deep from the shore. The theme for Kontiki 2016 is 'Jedi Knights', and you can see how some of the rafts have been decorated to match the theme.
Once the rafts launched,the weather (raining for most of the morning) improved briefly and I managed to get this photo of a rainbow. The organisers arranged for live GPS tracking of all the rafts this year, and this screen in the main tent shows the current location of all the rafts.
The Beaver Challenge is a series of challenge bases hosted for the Cubs and junior Scouts who visit Kontiki. Above are some of the bases from the challenge.

May 13, 2016

KonTiki 2016: Friday night raft construction

KonTiki 2016 is under way, with most teams well into building their rafts. Here are some photos of then shorefront. Teams build three rafts deep in most places, and once ready tomorrow, will help each other launch.

March 11, 2016

Bottlecutter2.0: making 'rope' from soft drink bottles

Image copyright Advocate Egerov

From Russia, via Youtube, comes this technique for converting a PET soft drink bottle into a strong 'tape' that can be used for lashings. Адвокат Егоров (Advocate Egerov) has two videos that explain how to build the Bottlecutter2.0 device to strip the bottles, and demonstrates how to use the strips to make lashings. Because PET shrinks when heated, he uses a hot air gun to 'frap' the lashings and tighten up the structures.
Image copyright Advocate Egerov
The first video (available with subtitles English subtitles) includes some basic lashings and instructions on making the machine to strip the bottle:

 While the second one goes through some detailed techniques and a rather elaborate willow branch chair:

Thanks to Clarke over at ScoutmasterCG for sharing this on one of his live chats- I recommend heading over there on a Tuesday or Wednesday morning (US time/afternoon European time)

March 4, 2016

'CatDrill' - quick pioneering with pre-drilled poles and light synthetic cord.

Catdrill 'lashing' details
'CatDrill' is an Italian technique for staving or lightweight pioneering, that involves preparing the staves to be used by drilling a small hole and notching the surface of the pole. Lightweight synthetic kernmantle rope is then used to tie the staves together, using stopper knots on the starting end of the rope, and simple slipped hitches to end the lashings. Their English website has a series of PDF documents that guide you through the basics, from preparing your poles, to the different types of lashings, and some basic projects. The original, Italian site has some more projects that are not yet translated into English, but the pictures speak for themselves.
image courtesy Scout Trento 1
According to the authors, they developed the technique for the following reasons:
CatDrill is born for solving the following problems:

  • the price of the building material (wood) and the difficulties found to get it from the forester;
  • the price of the rope;
  • to avoid the hazard of moving heavy wooden poles (and the tools needed to work with them);
  • to avoid ties, joints and toggle realized in the wrong way (we saw them too much times in pictures & co);
  • to practice pioneering during our one or two days trip, doing it quickly and avoiding to use the ground both as a chair and as a table;
  • to approach how a boy thinks, who wants to see concrete results as soon as possible.
1at Blairgowrie demonstrating Catdrill at Gauteng Region training workshop
Senior Scouts and Scouters from 1st Blairgowrie Scout Group recently introduced me to the technique and demonstrated it at a pioneering workshop at Arrowe Park towards the end of 2015. The technique saves time, produces strong structures and is worth investigating if you have some light staves/laths you can set aside for this technique.

There is a similar, more permanent technique called 'Froissartage' using carpentry jointing techniques which I have written about before.

Hat-tip to ScoutmasterCG and 1st Blairgowrie Scout Group.

February 26, 2016

Floating School in Lagos, Nigeria: Rafts in architecture

Image courtesy of NLE via their Makoko Floating School press kit.

Makoko is a floating slum neighbourhood in Lagos, Nigeria, built on stilts and rafts across the Lagos Lagoon. NLÉ is a Nigerian architecture firm who designed this floating school in 2013, to provide a teaching and learning space in this very crowded area. The solution wouldn't look out of place at KonTiki.

All images courtesy of NLE via their Makoko Floating School press kit.

While this project doesn't use lashings, it does make use of round laths, plastic drums and plywood, like a Kontiki raft. Here's some information from their press kit:
 The 220sq.m A-­‐frame or pyramid building is 10m high with a 10m x 10m base. It is an ideal shape for a floating object on water due to its relatively low center of gravity, which provides stability and balance even in heavy winds. It also has a total capacity to safely support a hundred adults, even in extreme weather conditions.

The building has three levels. The 1st level is an open play area for school breaks and assembly, which also serves as a community space during after hours. The 2nd level is an enclosed space for two to four classrooms, providing enough space for sixty to a hundred pupils. A staircase on the side connects the open play area, the classrooms and a semi enclosed workshop space on the 3rd level.

The simple yet innovative structure adheres to ideal standards of sustainable development with its inclusive technologies for renewable energy, waste reduction, water and sewage treatment as well as the promotion of low-­‐carbon transport. Furthermore a team of eight Makoko based builders constructed it using eco-­‐ friendly, locally sourced bamboo and wood procured from a local sawmill.

Construction began in September 2012 with floatation mock-­‐ups and testing. Recycled empty plastic barrels found abundantly in Lagos were used for the building’s buoyancy system, which consists of 16 wooden modules, each containing 16 barrels. The modules were assembled on the water, creating the platform that provides buoyancy for the building and its users. Once this was assembled, construction of the A-­‐frame followed and was completed by March 2013. Makoko Floating School is now in regular use by the community as a social, cultural and economic center and recently welcomed its first pupils who now use it as a primary school.
All images courtesy of NLE via their Makoko Floating School press kit.

October 23, 2015

Skylon Tower mk II- suspended tower by Bothasig Rover Crew

1st Bothasig Rover Crew previously built a suspended tower, which fell a little short of their own high expectations for it. Having conducted a thorough SWOT analysis of the construction, the crew headed out to Hawequas Scout Ranch to build an improved version.
After six hours' work for 16 Rovers and Senior Scouts, the new tower successfully stood suspended one meter off the ground. 

Here is an excerpt from the project report, discussing the overall objectives:
In hindsight, our objectives could have been more precise in terms of how high we could raise the 
tower. Our objective was to simply outdo the Mk I tower in height raised and to do it without 
incident, which we did achieve with a raised height of 1m and no reported accidents. 
Considerations in achieving the objectives 
In the planning phase, it is possible to roughly predict the final height raised based on factors such 
• The height of the apex of the tripods in conjunction with the distance of the apex from the 
centre tower. These two factors have the greatest influence of the final height raised, and 
the remaining factors will merely maximise the geometric potential of the layout. 
o The higher the tripod apexes, the greater the potential is of the tower to be raised. 
Also, the greater portion of the pulling effort will be translated into a vertical 
component of force to pull the tower up (as opposed to the horizontal component, 
which is destructive in this case and should be kept to a minimal). 
o As with the previous explanation of the height of the apex, the same applies with 
the horizontal distance of the tripod apex to the centre tower. The closer the apex is 
to the centre tower, the greater the vertical component of the effort in the system. 
• The block and tackle ratios should be considered and based on the size of the structure, and 
the size/strength of your team.  
o We used a 3-2 pulley system, and had two people pulling on each of the 4 tackles. 
o This simply diagram should illustrate what kind of mechanical advantage (MA) you 
can obtain from each system. 
To work out the MA, you have to count the number of 
lines between the blocks and exclude the running end 
from the count. 
o The greater the MA, the better, but this will obviously 
be limited by the resources available to you. 
o We used a 3-2 pulley system which gave us a MA of 
• The man power is a consideration and should be maximised, especially if you are resources 
are limited with regards to the pulley system. With this construction, it is possible to have 
the team sub-divided to work on various components simultaneously.  
o If the size of the team is large enough, you can have people placing anchors, building 
the tripods, building the crow’s nest all at the same time. 
o When erecting the central pole, we had 40% of the team hauling on one guy line, 
50% lifting and supporting the centre tower, and 10% holding the opposing guy line 
to prevent any over shooting of the tower. 
o When raising the tower, we had two people per tackle and one person per guy line. 
Then we needed extra people to lock the block and tackles and to secure the guy 
o We had between 9 and 10 people to build the structure, and 12 people to raise the 
structure. More would have been better because we had to let one person on one of 
the tackles to let go and run to lock the black and tackle, then tie off the line to the 
anchor, then those two from that anchor could assist everyone else, which is not 
ideal. "