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March 21, 2024

The Tilting Mast tower



This design was included on the JOTA/JOTI resource CD, originally in Dutch and published here in English for the first time:

Diagram of a tilting tower
Figure 1

 

The tilting mast consists of two parts: 

  • The pedestal 
  • The tilting mast 

The pedestal is based on triangular construction, which makes it very stable. Two long posts are connected at the top with a shear lashing to create a trestle. This trestle will be slightly inclined when standing and is therefore held upright by two posts, each of which is attached to one post of the trestle with a shear lashing. 

 

 

Figure 2

 These posts are secured at some distance below the top of the trestle. The strut posts must still have some length above the shear lashings, because after expanding the whole, V-shaped openings should be created above these lashings in which the axis of the tilting mast will come to lie. 

 

Figure 3

The cross girder, which is shown in figure 3 below the fork lashing of the A-trestle, primarily serves as a stopper pole for the mast and then keeps the mast in a vertical position. The location of the attachment on the trestle depends on the thickness of the mast, the thickness of the shaft and the oblique angle of the A-trestle. Hinged through the shear lashings, the A-trestle and the two strut posts are successively extended. In order to maintain the expanded corners, the uprights of the pedestal thus created are connected to each other by means of the cross girders. In figure 1 only the sleepers between the piles of the A-frame and the associated strut piles are drawn. However, the sleepers can also be fitted between the piles of the lower trestle and between the two strut piles. The lashing to be used is the square lashing.

 Figure 4 shows the supporting mast, which can consist of two or even more long poles which are attached to each other in line by means of round lashings. This carrier mast is attached to the axle pole with a square lashing. It should be noted that the bottom part of the supporting mast on which the counterweight can be attached, must be shorter than the distance from the axle to the crossbeam between the posts of the A-trestle - otherwise you won't be able to raise the tower all the way up!

Figure 4

 

 Figure 5 shows how a trestle is fixed at both ends of the axle-pile, which is perpendicular to the support mast. The distance from the shaft to the top of this trestle must be wide enough to allow passage of the top of the A-trestle, which serves as a pedestal. At the top of the A-trestle attached to the axle-pile and at the ends of the axle-pile, the upper part of the support mast is rigged with three ropes. 

 

Figure 5

 Next, it is the turn of the pedestal and the mast to slide together. The pedestal is placed on the ground in such a way that the A-trestle rests on the bottom with both posts. The top is now lifted slightly, so that the mast is slid under it lengthwise, until the axle ends up in the two V-openings. This is held in the openings by two guy wires, which are bolted to the ends of the axle-pile and tied to the sleepers at the bottom (figure 5). A rope is also tensioned from the top of the trestle on the axle to the bottom of the tilting mast, so that the last top guy is also under tension. Furthermore, a rope is attached to the underside of the carrying mast with which the mast can be tilted into a vertical position. With combined forces, the trestle is placed on its legs at the intended place. These legs can also be buried in the ground if necessary. During the erection, the trestle will be in a tilted position. It is then checked whether the tilting is working as expected. Then the antenna is attached to the top of the mast. This increases the weight on the load arm. The force needed to pull the mast vertical again can be reduced by attaching a counterweight to the bottom.

December 15, 2021

New Instagram account and site news

QR code linking to @ropesandpoles on instagram

So it's been quiet here for a while... alongside everything that's been going on in the world over the last two years, I'm now the father of a one year old girl! Over the last 18 months, Rovers here in South Africa have been involved in community service, and you can read about some of these projects here:

Coming back to pioneering, I've started an Instagram account for the blog at @ropesandpoles, as well as the existing channels on Facebook and Twitter. Over the next few weeks, I'll be posting some of my favourite projects from over the years on the Instagram feed, and I have a few new posts queued up for you to read in January. As always, I'm interested to hear about any interesting pioneering projects you've seen, so please feel free to contact me with this form and I can share your project with the world.

June 23, 2017

Ropes and Poles at the World Scout Moot, Iceland


I'll be travelling to Iceland for the World Scout Moot from the 25th of July to the 2nd of August this year. I don't have any plans to do pioneering while I'm there (Iceland doesn't have too many trees and bringing my own poles from South Africa would be tricky), but I'm keen to meet up with anyone who'll be there.



I'll be working as a Tribe Advisor, so I'll be based in Hafnarfjörður during the Expedition stage (26th-28th July) and at the main campsite in Úlfljótsvatn the rest of the time. Contact me (as a comment here, via email or on twitter) and we can arrange to meet. I'll have some Ropes and Poles patches to trade, and am looking forward to meeting you.

June 16, 2017

Minifig gateway at KonTiki 2017

I've featured gateways built by Harmellia Gardens Air Scouts before, and this Lego-inspired gateway at KonTiki 2017 is their latest design. Harmellia are using a synthetic hawser-laid rope, which, unlike braided polyprop ropes, behaves in a similar way to traditional sisal cordage. the head of the structure is bent from smaller thatching laths, and car tyres make up the hands.

(more sculptures, including dinosaurs, superheroes, biplanes and birds, on the sculpture tag)

June 9, 2017

Elevated tent platforms at KonTiki 2017

In rainy weather (and KonTiki frequently brings rainy weather), it can be a good idea to get your tent up out of the mud. Bush Hill Scout Troop built this four-tier stepped tent platform for their campsite at KonTiki 2017. The two highest tiers had enough clearance underneath to be used as part of the campsite as well.

I wrote about a three-storey tent tower built by 1st Walmer Scout group in 2012 


May 26, 2017

Everything was awesome at KonTiki 2017

KonTiki 2017 took place recently, and was the coldest  and one of the stormiest KonTiki weekends in some time. In spite of the rain, wind, hail and frost, 55 teams arrived to camp, taking part on this year's theme of "Let's Play!"

 Friday afternoon saw a hail storm that sent many teams running for shelter, but by the time I was on site in the vening, construction was going ahead under lights along most of the shore.


This year, many teams had LEGO-themed decorations in their camp sites, from bricks and blocks to minifigs.

The poor weather continued on Saturday, and in the end about a dozen teams spent the hwole night on the water through the wind and rain - here they are the next morning, when the sun came out for a beautiful sunrise and morning.

Congratulations to the over all winners, 1st Eagles. The full, detailed resulsts scoresheet is available here.

I'll be taking a closer look at some of the campsite details from this weekend in the next few weeks.

January 27, 2017

Kontiki 2016 timelapse videos


The KonTiki organisers have launched the website for the 2017 competition, and along with it, a series of timelapse videos from last year's event. These videos give you an idea of the work that goes into the weekend (and also of the unseasonal rain we had last year).