[TowerTalk] Temporary guys ???
Roger (K8RI) on TT
K8RI-on-TowerTalk at tm.net
Thu Feb 11 08:02:17 EST 2016
My Thoughts and I claim no responsibility for any results from the
following statements!
I'm going to disagree with those before me (at least a little)
Rule #1. Never forget: Tower work is dangerous at any height, Period!
Rule #2 You can get killed from a fall from any height if you
land wrong. Your chance of survival goes down rapidly above 10 feet.
Doesn't sound like much.
If you land right you' may feel like you wish it
had. Like on the D-day channel crossing. My cousin said they were so
seasick they were afraid they were going to
die...Then they were afraid they wouldn't. Land flat on your back on
"soft" ground and you likely won't be able to breath for a minute or
two. That's a scary feeling! I have done just that. No
it wasn't a tower and I was only 16 at the time.
OTOH You can get killed around tower construction on the ground
by walking into stuff, tripping and falling on stuff, or having a wrench
dropped on you..
Rule #3 The less you know the more likely you will fall, or be
injured, even if you do every thing correctly.
There are more, but this should be enough for now.
Contrary to popular belief, a real 25G is not a strong tower by itself.
A "Proper" installation can make it relatively strong and tall!
Being a fussy old man who has climbed many towers , some of questionable
safety and a few which I found to be downright unsafe that scared the
crap out of me, and I'm still alive and unhurt (at least from climbing
towers).
Stretchy guys scare me! Three in parallel still scare me, but not as
much! It takes very little movement at 30 feet to break a tower at the
base set in concrete. At 30 feet I probably would be relatively
comfortable if the other climber stayed close to the tower and didn't
throw his weight around. To begin, I said climbing is dangerous. So is
lifting and setting a tower section in place without a gin pole.
Yes gin poles are easy to build, but building a safe one does take a
little more thought. I've built them out of galvanized 1.5" steel fence
rail that were strong enough to safely handle 45G sections. I've built
2" diameter Aluminum gin poles that reached 20 feet above the mount with
swivel arms on top that were safe if used properly!
Always use a pulley at the base of the tower so the rope to the gin
pole*always* runs vertical. I've seen hams pulling to the side with the
pole bent to an unbelievable angle and it still held, but they were
inches away from a serious injury or worse. Many will say they did that
without a problem, but they are apparently unaware of the danger in such
a move!
Many have also lifted the next section successfully, but that too is an
unsafe operation. With experienced and strong climbers it is less
unsafe, but it never a safe action. Think of where your feet must be
for a person to lift that next 10 ft section high enough to set it in
place. Two 180# (with equipment) climbers would have their center of
mass about 5 feet above the last section if they can hold the next
section in the middle so it's not top heavy. that's 180/2*2 or 180 plus
about 30# for the entire section = 210#, 5 feet above the last section.
Even at 30 feet they likely exceed the tower ratings for lateral loading.
If I were you, and I'm not, I would beg or borrow an adequate gin pole,
study its safe use and go that way.
TOWER BASES not plumb: It depends on the height, load, and tower's real
strength. . You neglected to give the total height of the finished
tower. ! That's important. You did say, "Within tolerance". The tower
builder's tolerance? Do not expect a clone to be as strong as the real
thing. They are cheaper for a reason. They may not use as strong
materials. They may not use the same bracing and they certainly do not
have the corrosion protection. That's not to say they can not be used
safely. They certainly can, when their limitations are taken into
consideration. Do not use ROHN's specifications for load in wight, or
wind handling capability. If those figures are not available, I'd
derate it by at least 25%, if not more compared to a 25G.
NOW, IF the tower is plump within "real" and practical specifications
AND it's plumb within those specs, it should be safe as is, At "least"
to 40 feet with a small tribander or a couple VHF, or UHF antennas.
I've used many clones including an American Steel to 90 feet, but I
don't recommend it and I would definitely not treat a clone as if it
were a 25G
73
Roger (K8RI)
On 2/10/2016 Wednesday 10:59 AM, jimlux wrote:
> On 2/10/16 7:24 AM, Douglas Ruz (CO8DM) wrote:
>> Hi,
>>
>> I just started installing the tower...it is Rohn 25G clone.
>>
>> I have a buried base...about 3 ft deep in concrete 2 x 2 ft.
>>
>> I add the 2nd section and i add temporary guy ropes. I am using
>> Paracord 550 ropes...single paracord ropes is 4mm diameter and handle
>> up to 550 pounds, it strech a little, so i used 3 ropes per guy (12mm
>> diameter and more pounds to handle)...3 + 3 + 3...
>>
>> Do you think it is OK to climb and add the 3rd section with permanent
>> guys?
>>
>> A gin pole is not available, so we are TWO hams climbing the tower.
>>
>> Thoughts ??
>>
>
> There's no "official" way to know.
>
> It's really about whether YOU feel safe. You're only up 20 feet.
> (granted, a fall from 20 feet can kill you). I'd not feel too
> nervous, but I'm not you, and my risk tolerance isn't yours. Just like
> when rock climbing, I'd want to look at it, shake it, and see how it
> feels.
>
> I'd feel more safe on a 20-30 foot high stack of Rohn25 with rope guys
> than I would, for instance, on a 30 foot extension ladder leaning
> against the side of my house, particularly if I were horsing around a
> 50 pound tower section.
>
> Is it unequivocably safe? Can you and your partner up there swing back
> and forth to get it really swaying without a failure? Probably not..
>
> 20 feet is also close enough to the ground that if things seem a bit
> wobbly when you get up there, you can quickly downclimb.
>
> Compared to being 100 feet up, that's a huge difference.
>
>
> If you've got a step ladder as a fulcrum, have you considered just
> stacking your 3 sections on the ground (horizontally) and then tipping
> them up, then mating with the section sticking out of the ground?
> Yeah, 30 feet and 150 lbs of tower is a bit unwieldy but it might
> actually be easier.
>
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>
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--
73
Roger (K8RI)
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