Rigging a gin pole

[frackers]

I've got my 11m 100mm steam pipe mast fixed to its swivel base and the guy wires set up for the two sides and the backstop (a very conventional setup of 4 wires at 90 degrees to each other). I'm not sure how to use the gin pole so I'll tell you where I've got to so far.

The gin pole is 4m long and fits into the swivel base of the mast at 90 degrees to it - pretty obvious so far!! I have 4 links of 2 tonne chain welded to the top of the gin pole so I can choose where I connect a shackle onto the 'front' guy wire which has been made with a turnbuckle adjuster at 10.8m down so there is an attachment point for the gin pole. Is this right or should I just arrange for the guy wire to slide through a shackle on the end of the gin or should it be attached as I have it,

From the turnbuckle, I have two wire ropes - a short one which will connect onto the anchor point and a longer one, on a shackle I can remove once erected, that I can hitch onto the tractor to pull the whole lot up. This is where I hit a problem!!

As I pull up, everything is fine until I reach the point at which I have a straight line from the top of the mast, through the top of the gin pole to the back of the tractor. At this point I have to remove the shackle from the guy wire to the gin pole otherwise I'm pulling the gin pole out of its socket at the swivel base as I drive the tractor away. I also end up with the tail that should connect to the anchor point being up in the air.

Possible solutions:

• run the 'pullup' wire through the anchor point, so the guy wire is lined up to shackle the wire to the anchor - this means disconnecting from the gin pole at some point but probably lower down that my current (failed) attempt
  
• run the 'pullup' wire through a pulley 4m out from the swivel so that the gin pole is pulled straight down to the horizontal - this means that the tail going to the anchor point won't reach until I disconnect from the top of the gin pole. I will also need to cast in a tonne of concrete as it will be a vertical pull!
  
• use a totally separate 'pullup' wire from the top of the mast via the gin pole so that the front guy wire hangs loose until I connect it to the anchor - this requires another trip into town to get another wire rope made up and I end up with a wire dangling off the mast all the time it is up.
  
  

So what is recommended?

Cheers

[electronbaby]

Usually the way it is done is that the wire rope connecting the top of the tower to the end of your gin pole (this is called "hoist side") is never removed, and the tension is always fixed by your turnbuckle. There is another turnbuckle that needs to be placed below the gin pole, and this is what attaches the gin pole to the in-ground anchor.  This way, when the tower is raised vertical, your gin pole will be NEAR HORIZONTAL (in actuality, it should be at 5 - 10 degrees tilt) to allow enough room under it for the anchor turnbuckle. The turnbuckle or shackle can then be installed when it is in this position.

The lifting of the tower is usually done with two pulleys  and a fixed anchor point. The hoist cable will attach temporarily to the ground anchor with a removable shackle. It then will go up into the air and wrap around a pulley (snatch block) on the end of the gin pole. the cable will then come back to the ground and wrap through another snatch block temporarily attached to the ground anchor. After it passes through the anchor, it will go to your tractor, to tension it (I use a winch normally). When you pull on this cable, it will cause the two pulleys to be pulled together (This will reduce your pull force by half) and the gin pole to be pulled toward the ground and therefore, the tower to go up.

You would normally use an "equalizer plate" on the ground anchor so that it would facilitate the connection of blocks and shackles at the same time, while still allowing you an extra center hole for the last turnbuckle to be installed when the gin pole is ready to be locked down. After it is locked down, all temporary rigging used for the lift, can be removed.

Not to confuse you more, but you should think about positioning the side guy anchor lines a few inches toward the down side anchor. This will allow your side guys to loosen slightly when you come off center with the tower and it is starting to be lowered. It might help you to not break a cable if your guys get too tight, and therefore is a little safer.

Hope I didnt make it too confusing. :-)

[frackers]

Not at all confusing Roy - the only issue I have with this method is that the angle of the guy wires is then limited to the length of the gin pole - I have laid out the anchors at 10m out from the base so that the guys are at 45 degrees. I was expecting to remove the gin pole after raising the mast.

I have the side anchors slightly offset (by accident as it happens, the thickness of the fence posts that form the anchors) so I slacken off as I come off the vertical so I'm happy with that!!

I think I'll work on option (1) where I pull up through the raising side anchor point (even though it is twice as far out from the base as the length of the gin pole).

Its what experimentation is all about after all :-)

Cheers

[TomW]

frackers;

Go over to http://bergey.com/ grab their Xl1 installation manual it is 450 KB but well worth the download:

http://bergey.com/Products/XL1.Tilt.IM.4.pdf

Very useful info even if its not Bergey you are raising. It is a pipe mast tower so very similar principles.

Good luck with it.

Tom,

[frackers]

Thanks for the input Tom - the information about anchors particularly has made me hold the concrete mixer for a few days whilst I think about it.

I was going to use waratahs at 90 degrees to the guy wires to reinforce the fence posts I have so far - it looks like the anchors should actually be in line with the guy wire and the concrete pad well buried. I think 25mm rebar with a loop on the top and a couple of angle iron cross pieces on the bottom will do a better job. It will be easy to dig the necessary holes are they will be stepped back from the posts so I'll have plenty of room to work on them.

I'm feeling much happier with the feedback from you guys - its certainly tickled the old grey cells:-)

Cheers

[Norm]

I've seen it done this way





initially cable runs over top of roller in fork at

the top of gin pole....then about half hoisted it

is pulling directly on the anchor point of the mast. All other guy wires as Tom directed you to

link.

[Norm]

Well not quite accurate....the hitch point will

be farther away from the base of the mast  of

course as your tractor moves away.....

[electronbaby]

This might work for small towers. I would not try it this way for anything substantial. There is too much room for error.

When I pull up a 90' or 100' tower there could be as much as 8000 lbs. of lift force required to get the machine off the ground the first 30'. This is due to the weight of the machine on the end of a long lever. Also the machine weight and the tower weight.

Pulleys are your friend.