Ropes and Poles

Over the next few weeks I'll be posting some new content to the site. We've also had exciting news: Kontiki, the annual rafting event I have blogged about, will be hosted at Arrowe Park, the local campsite where my Scout Troop and Rover Crew meet. Expect lots of coverage from Ropes and Poles.

The previous post, documenting the Knight's Trebuchet, was featured on Google SketchUp's blog,  as part of the Make Ideas Real project. If you've built this or any other project from the blog, please let me know, I'd love to see your photographs


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I designed this simple trebuchet  as a more stable, robust small trebuchet. The two opposite side frames are braced against each other so it doesn't need guy lines, which is the main problem with the older trebuchet design on Ropes and Poles. The Troop Scouters of the recent Gauteng Scout Wood Badge course at Arrowe Park tested it out and verified that it works (two of the patrols promptly ganged up on the third to send a shower of over-ripe tomatoes across to them). The theme of the Wood Badge weekend was 'the Knights of Gauteng' so this is the Knight's Trebuchet.

Two patrols used a traction rope as per the drawing below, while the third patrol used a rubber tube, pictured above. All three worked successfully.

Here are the sequence drawings for assembling this trebuchet:

1. Build one 'A frame'- make sure there is enough space at the top for the throwing arm to rest.

2. Tie the base lashings of the second (yellow) 'A frame'/triangle and attach it to the first A frame

3. Lash the top of the yellow A-frame, making sure the crossing lines up with the green A-frame

4. Lash the two base poles on to the two frames.

5. Attach the throwing arm, which is lashed onto it's axle. Rest the axle in the forks on the top of the a frames, and 'mouse' the top of the fork to prevent the arm jumping out.




This trebuchet was tested with and without a sling.

The SketchUp model is available for download HERE.

  The annual Kon Tiki Chairman's Challenge was held all across Gauteng province recently. The top ten teams from Kon Tiki in March were challenged to participate. Rather than the normal race down the Vaal river, the challenge this year consisted of building a raft and completing a mobility challenge at four different lakes across the province, starting in the East at Arrowe Park, then on to the old quarry at Eastleigh Sea Scouts, then Emmarentia Dam and ending at in the West at Gilwell in Florida.
The rafts were all lightweight and designed to be quick to assemble, because this would have to be done four times. Points were also given for  advertising Scouting on the vehicles used to transport the rafts between the four lakes. Two groups, 1st Kengray BK and 1st Kempton Park,  built rafts with light plumbing pipe outriggers, pictured above. Most other troops built very light 6 barrel rafts as shown above left. The competition was won by First River Trail Scouts.
More photographs are available on the Kon Tiki Facebook page.

Robin Hills Scout troop built this portcullis gateway for their campsite at Kontiki 2011. Two A-frames support a gate that slides up along the slope of the front legs. This gate is a much bigger and sturdier portcullis than the one I blogged about back in 2006. The SketchUp model is available for download here.

Here is the gate closed at left, and open on the right.



A photograph of the gateway. Robin Hills went on to win Kontiki