Portawrap minimun wrap, add'l wrap nomenclature

[southsoundtree]

I was taught to say “run it through” when needing to run it through the system with no wraps. We also would not use the top cleat, as it would most often slip off in a negative rigging situation when it would flop in the slacking moment.

I have a very different, exclusive meaning for "let it run". Contrast: "snub it off"/ "lock it off".


That flip is a major strike compared to a fixed bollard.

 

[Bart_]

Chart might have been Dan Thornton. Wasn't Treespyder. Maybe on a BMS spool thread.? Spool has three different wraps settings whIch I made a "chart" for - might be the connection.

 

[Bendroctanus]

I have a very different, exclusive meaning for "let it run". Contrast: "snub it off"/ "lock it off".


That flip is a major strike compared to a fixed bollard.

There’s a distinction between “let it run” and “run it through.” I know Letting it run very well. I’ve had riggers who did not and watched me be violently sprung around. Luckily I’m pretty decent at bull riding.

 

[southsoundtree]

As to calling out specific wraps, rig small to start then trust in the porty operator. Feedback if needed, but generally "same size, bigger, x diameter etc" and whoever is running ropes will make the call based on how the previous rigs go.

edit (unintended partial post that's been finished):

I try to have conversations with crew about how things went, how much effort is being exerted, how stable things feel. If things are amiss, Stop. Adjust the plan. Nail it.

For the effort of a Maasdam rope-puller being advanced, the pull-force on a test-pull of a hand-pulled line, the overall effort that was required for a certain task like a piece that was pulled over or was lowered, I like to use a 0-10 'call and respond'.




Tensioning:
Groundworker:"That's a one-hand pull at 5 on the rope-puller"

Sawyer: "one-handed 5"
Or
Groundworker: "2 handed Pull of 7-8"
Sawyer: "2 handed, 7-8"
Sawyer: "Let's adjust the plan. Let's add another rope"
or "add some MA" or " more wedges."
Groundworker: "Let's adjust our plan, add a..."





Catching loads:

Roper: "easy catch, 2-3 to catch and lower"
Sawyer: "2-3".
Sawyer: "the next piece will be about 1.5 times the force"
Roper: 1.5 times as much as the last one.
Roper: adding a half wrap for the next. Minimum installation plus a half.
Sawyer: "Minimun plus an additional 1/2.
Cut and catch
Roper: "easy catch.3-4 on effort"
Sawyer: "3-4".

There’s a distinction between “let it run” and “run it through.” I know Letting it run very well. I’ve had riggers who did not and watched me be violently sprung around. Luckily I’m pretty decent at bull riding.

I read that wrong.

 

[Serf Life]

For the effort of a Maasdam rope-puller being advanced, the pull on a test-pull of a hand-pulled line, the overall effort that was required for a certain task

I'm missing what you're explaining if you could explain a different way? Using those as examples of how to run a porty?

 

[southsoundtree]

I'm missing what you're explaining if you could explain a different way? Using those as examples of how to run a porty?

Sorry. That was a partially written post about communication that was not meant to be posted until finished.


Fixed, above.

 

[Evo]

Sorry. That was a partially written post about communication that was not meant to be posted until finished.

Irony…. Sounds like sumthin I’d

 

[southsoundtree]

Irony…. Sounds like sumthin I’d

Family came in and I set down my phone, probably bumping 'Post Reply'.


Forum discussion fills waiting time. Might have been waiting outside the Fitting Room while shopping for summer camp.

 

[southsoundtree]

I rarely use a regular POW. Most often it's climber rig/ cut/ lower on NC (with it without a leather cambium saver with/ without stubs (zero marketing department, zero blingy anodizing, good bend radius, remotely installable, lightweight, portable, free, etc), the BMG grapple bollard, rarely the BMG Belay Spool or Rig'n'Wrench, my GRCS on one job, and my Stein fixed bollard is getting very dusty while waiting for the first day at work.

As to calling out specific wraps, rig small to start then trust in the porty operator. Feedback if needed, but generally "same size, bigger, x diameter etc" and whoever is running ropes will make the call based on how the previous rigs go.

I think that with an experienced, confident operator, this is ideal.

With teaching someone, it's hard to let them do what they think is best when working with a very limited data set and trainee nerves.

 

[southsoundtree]

When I am not cutting And catch/ lower/ landing the 'work', my common plan is for the groundworker to catch the load, them pass the load to me, giving me a way to help/ work and reducing their tasks, freeing up hands.

As practical, I'll use a rope that is less than double the height of the rigging point so that the standing end is off the ground before the rigged piece can land on it.




I just found a micro-porty in my gear that slipped my mind. I'm going to use it for climber , maybe with some 3/8", allowing porty-level loads, easy adjustability, and less wear and tear with the ability to reduce/ remove hold-back force while groundworkers land bigger pieces, dicing the piece up to cause gravity/ branches/ rope to guide the piece into the drop zone in a small enough size or muscle it over, if needed.







At the same time as POW beats stubs,
non-anodized, non-powder coated, weightless, non-marketable stub wraps offers options that a PoW doesn't.

With the ability to use momentum, quickly reduce and drop all wrap friction, then back to snubbing off or decelerating a piece on stubs, with quick decision making, I regularly lower/ land big pieces 'on the swing' , watching from Above, with nobody in the drop zone in ways that are probably harder to see from the ground or requires a lot of confidence in not breaking obstacles with fast reading and respond to the situation. Double whip tackle ( natural crotched or sling/ biner in the wood) halves the load on the rope.



If it's not going to be able to lay down 'on the swing', I'll stop the 'work' in an advantageous position where I can manipulate the working leg of rope to get the piece to tip a desired way and be able to be laid down, with or without assistance.

Stubs can go from strong hold-back power to free very quickly.
Very fast to wrap into a tensionless hitch and be hand free, lickety-split.

Also, no need to install/ remove/ stow/ re-install when desiring aerial friction.



A time and place for everything.

 

[southsoundtree]

Stubs, the original fixed bollard!

 

[Mick Dempsey!]

As you know Sean, I’m a big advocate of NC rigging and climber lowering in the right circumstances.


Just as an aside, I’ve been caught out a few times over the years by certain species at certain times of the year, specifically poplar in spring when the bark can separate from the cambium very easily, leaving a smooth well lubricated surface underneath.

So if you use a stub and it’s a decent piece your ‘friction device’ can very quickly turn into a very non friction device and your piece gets out of control in an instant.

 

[Bart_]

All my first double whip lowering was done off natural crotch and stubs. It seemed inescapably logical to do. Then I realised you could add more gear to the mix. Free form bollarding Fortunately I never experienced springtime cambium natural lubrication. Never did bigger pieces. I did double whip for aerial control rather than increased load capacity.

 

[Bart_]

I found this in a 2023 post of mine:

"
Courtesy of Kenny I'm more aware of the non-linear nature of wraps. They're exponential. A similar device measured:

W34 1/2 wrap BMS belay spool tension ratio 1.9 mu 0.20
W35 1 1/2 wraps BMS belay spool tension ratio 6.6 mu 0.20
W36 2 1/2 wraps BMS belay spool tension ratio 18 mu 0.18

Notice adding 1 wrap kicked the ratio from 6.6 to 18! Portawraps are also wrap bollards just with some redirecting added. Extra wraps have big effect."

Rough engineering math: 1/2 to 1 1/2 wraps increase tension ratio x3
1 1/2 to 2 1/2 wraps increase tension ratio another x3

Could be a portawrap pattern x3 higher load per additional wrap

I had no success finding the porty chart post yet.


edit - At first I thought it was too bad I didn't have per 1/2 wrap data. Then it occurred to me that since each increment multiplies the previous level, two equal factor increments that multiply to 3 " - leads to sqr root 3 = x1.73 load increase per additional 1/2 wrap. The same thing can be done for porty's with 1/4 wrap pins (if x3 per wrap, sqrt root 1.73 = x1.3 load increase per additional 1/4 wrap).

All that remains is to get the few baseline measurements for your rope and model of porty combo. Once you get the base tension ratio (90 deg redirects) and the per wrap "times" factor Bob's your uncle as we sometimes say. You know how hard it is to hold the rope for lowered piece weight.

 

[Bart_]

One other aspect - Dynamics

Let's take an example porty that works a bit better than the BMS at 2 1/2 wraps - let's say it achieves a tension ratio of x20 or 20:1 instead of x18, to make the math easier.

To hold the log still:
tiny log 20 lbs only takes 1 lb at the groundie's hand
200 lb log takes 10 lbs at the groundie's hand
2000 lb log takes 100 (!) lbs at the groundie's hand - clearly going to be trouble, more wraps please

To catch/stop a falling log you need more than 1G of acceleration (deceleration). By feel, 1.5 G's is moderately soft. This means more force than statically supporting log weight. Our example becomes:

To catch/stop falling log applying 1.5G's:
tiny log 20 lbs x 1.5 = 30 lbs only takes 1.5 lb at the groundie's hand
200 lb log x 1.5 = 300 lbs takes 15 lbs at the groundie's hand
2000 lb log x 1.5 = 3000 lbs takes 150 (!) lbs at the groundie's hand - clearly going to be trouble, more wraps please

This is where having the basic per wrap loading factor for your porty can make life easier. If it's x3, going to 3 1/2 wraps: 150 lbs / 3 = 50 lbs groundie. Going to 4 1/2 wraps: 150 lbs / (3x3) - 16.6 lbs bingo.

The harder or more quick the stop the higher the G's applied and you could see how the numbers would go up. So you have to allow headroom for catching, not just supporting the log's weight. I'm estimating that running a rope at 10 lbs through your gloves is probably a comfort limit. It could be +/- of that depending on the person.

An astute student will note I've left out the 1.2:1 of the rig tip pulley but that's only 20% vs the big effect of choosing wraps to achieve enough tension ratio.

 

[Matias]

One other aspect - Dynamics

Let's take an example porty that works a bit better than the BMS at 2 1/2 wraps - let's say it achieves a tension ratio of x20 or 20:1 instead of x18, to make the math easier.

To hold the log still:
tiny log 20 lbs only takes 1 lb at the groundie's hand
200 lb log takes 10 lbs at the groundie's hand
2000 lb log takes 100 (!) lbs at the groundie's hand - clearly going to be trouble, more wraps please

To catch/stop a falling log you need more than 1G of acceleration (deceleration). By feel, 1.5 G's is moderately soft. This means more force than statically supporting log weight. Our example becomes:

To catch/stop falling log applying 1.5G's:
tiny log 20 lbs x 1.5 = 30 lbs only takes 1.5 lb at the groundie's hand
200 lb log x 1.5 = 300 lbs takes 15 lbs at the groundie's hand
2000 lb log x 1.5 = 3000 lbs takes 150 (!) lbs at the groundie's hand - clearly going to be trouble, more wraps please

This is where having the basic per wrap loading factor for your porty can make life easier. If it's x3, going to 3 1/2 wraps: 150 lbs / 3 = 50 lbs groundie. Going to 4 1/2 wraps: 150 lbs / (3x3) - 16.6 lbs bingo.

The harder or more quick the stop the higher the G's applied and you could see how the numbers would go up. So you have to allow headroom for catching, not just supporting the log's weight. I'm estimating that running a rope at 10 lbs through your gloves is probably a comfort limit. It could be +/- of that depending on the person.

An astute student will note I've left out the 1.2:1 of the rig tip pulley but that's only 20% vs the big effect of choosing wraps to achieve enough tension ratio.

I have never tried running a piece with 4.5 wraps, or even 4. I thought that more than three was effectively locking it off.