Help understanding advantage

J

JosefR

Location
Denham Springs
I'm a 52 year old sailor who needs to go 57' up a mast. I have rigged up some blocks and 240' line as in the 1st picture and attempted to hoist my 180#. Turns out, I can't lift #5 while I'm hanging from it, so I wound up pulling on #1. Problem was too much weight and line was slippery, even with leather palm gloves. Had it not been slippery, I probably could have done it, but it wouldn't have been easy. I think I have these numbered correctly, but if not, I think they are consistently wrong on both pictures. The fiddle block is ratcheting.
20170609_084258.webp
So I am asking if I re-rig as in the following picture, will I have better advantage when pulling on #1? I can still let myself down by controlling #5. And I assume I'll need another 60' of line.

20170609_084631.webp
 
You shouldn't need a 5:1 to lift yourself. A 3:1 should be plenty and will use much less rope. Try some latex palmed gloves, much better than leather.
 
First picture essentially a 4:1 with redirect. Second picture is a 5:1. I don't know that trusting that cam as life support is a good idea. Back it up with a prussik or at least tie a stopper knot when you get up there
 
4:1 and 5:1 is what I had hoped I was drawing. Stopper knot when I get up there was the plan, nothing else to tie off to.

3:1 is not plenty, since 4:1 was extremely difficult, regardless of the slippage. Wouldn't 3:1 be 60# per pull? That's a lot of weight to pull with one hand. I don't mind lots of rope if the pulling is easier.
 
Well I won't argue that nothing is wrong because I wouldn't be here if I knew better...I can say that the double fiddle is a very good quality new item with ball bearings, but the double block at the top is an old one found in my dock locker and probably doesn't have bearings.

The line was $100 for 300' on eBay.

I also have rigged up a 1/4" single braid hoist on the front of the mast for lifting dinghy and kayak on and off the boat, this one IS 3:1 using two more of the older double blocks (no cleat). Kayak weighs 80# and is barely manageable with one hand pulling. Gonna increase that on to 5:1 also.

Maybe my lines are crappy quality compared to yours? Maybe I'm just getting feeble...
 
Might be a dumb question, but did you use the correct sized rope for your pulley system? Over sized rope would lead to drag. I don't climb with that set up, but I have raised some heavy loads when rigging with a 3:1. You should float up on a 4:1 or more, depending on what kind of shape your in.

As a reference I am 260, and with that 4:1 I'd only have to pull 65lbs to get moving and only 52lbs with the 5:1.
 
Yeah, they are rated for 11mm or 7/16" line. I'm using 3/8", hard on the hands.
I did say I am pulling with ONE HAND on the 4:1 setup because I have to clear the line from the cleat.
On the 5:1 setup, I will be able to pull hand over hand.
If I had known, I would have tried the same setup at 3:1 where I would have had two hands to pull with, might have been easier, but that's still 60# per pull...
The 250 pound muscular 20 something youngster sitting next to me says 65# per pull ain't that easy...I'm sure you tree climbers are in much better shape than me.
 
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We're all in various stages of fitness. I am plenty strong and can throw wood around better than most, but would get winded trying to keep up with some of these other guys moving through a tree. So unless you are completely out of shape don't hold that against yourself, and if you are obviously being lighter and stronger would have it's advantages.

From what you've said I suspect the sheaves in your block are not a very large radius as they are designed for 11mm, that on top of the lack of bushings is probably where your trouble is. I would think you would want at least a 1.5" diameter sheave and a higher efficient bushing to make this work. It's only a mechanical advantage if everything spins freely
 
If you have a little money to invest in this you might get online and look at pulleys designed for climbing, they will be rated for life support and more efficient. Also look closely at your rope, figure out what the construction of it is and what it is rated for (hopefully it was new and not used/misused before you got it)
 
I figured at some point it would come down to the quality of my gear. I have quality line for my halyard and sheets, paid big money for them.

By the time it comes to equipment I plan to use when hell freezes over, I couldn't justify the big money. Ironically, it has cost me another 300' spool of line since I cut my first one in the 4:1 setup...if nothing else, I'll have a lot of extra general purpose line left over.

I'll test all this next weekend when I get back to the boat. Thanks for the help.
 
An easier technique would be to use both hands to pull up, lock your left arm, reach for and pull the slack out with your right hand. If you're able to reach the mast with your feet, you could use the hip thrust method, rather than just pulling up your dead weight.
 
I don't know if we are saying the same thing, I mean pull on rope #1 in your first drawing with both hands, not one on #1 and the other on #5.
 
Yep, that's what I was doing, 2 hands on #1 and then pull slack out on #5 while holding #1. Very strenuous. Partly the extreme gripping of the slippery rope ideas having to do.

Also didn't feel safe letting go of #1 to pull #5. I could picture fatigue causing me to lose my grip and the whole line slipping through.
 
Grippy gloves like the Atlas brand help a lot, not the nitrile type though. You could add a short piece of rope to your harness,or bosun's chair and tie a Blakes hitch to the #1 rope and not use the the cam cleat. The hitch will constantly grab the rope and hold you if you let go. The only way it can release is to apply pressure to the top of it. Once the pressure is off it grabs again.
 
It might save you from having to replace the rope. I think you made the right choice of using the fiddle block, with ball bearings over blocks with bushings, provided that the sheaves rotate freely.
 
Well, I've already ordered another 300' of line to test the 5:1, and I didn't upgrade the old double block I'm using at the top.

If I get this other stuff feeling reasonable, maybe I'll splurge and buy a double with bearings, only another $60.
 
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