Next generation snatch block

[Metcalf]

I finished up the design on my snatch ring 'block' device.





This works fantastic to keep the ring from 'tipping' over when the line becomes slack during a vehicle recovery. This keeps the line in the proper position on the ring and prevents you from having the lines saw through each other. The block is set to the same nominal thickness as the ring which minimizes addition friction at the ring if the soft shackle is attached to something with a smaller D/d than the aluminum ring. This is also good because the outside radius on the ring is small which can be a trouble spot.

If you need one, drop me a PM.

 

[Low_Sky]

Excuse me for overthinking the hell out of this, but couldn’t the same be accomplished with a rubber band? I get two nice fat sturdy ones every time I buy asparagus.

I have a scale prototype.

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[Metcalf]

Excuse me for overthinking the hell out of this, but couldn’t the same be accomplished with a rubber band? I get two nice fat sturdy ones every time I buy asparagus.

I have a scale prototype.

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I gave the rubber band idea a try, no matter how tight and how many rubber bands I used I couldn't get the soft shackle tight enough to prevent the ring from flipping sideways with a very light 'wiggle' test.



My block prevents that from happening under even rather violent motion.

 

[Low_Sky]

My asparagus and I stand humbled.

I’ll give one of these rings a try when they start hitting Amazon via China, and will remember the block/Velcro method if I have problems keeping the winch rope seated.

My rigging’s movements are never too violent when I winch, so I’m doubtful it will be an issue for me.

 

[Kruse]

Metcalf!
I like your design. Agree that it needs to stay put under non extreme movement.
Your block is quite large though. How about this idea:
- Since the sides by the soft-shackle does not need to be very ridgid,
- If you make the block in a "U" shape and use a hook and loop to keep each "leg" in place,
- You could then "reverse" the "U" onto/ into the ring for storage, maybe even have it "clip/snap" in for safe keeping.
How flexible can you make those legs on your 3D printer? Is the plastic brittle or are there softere materials available to print?

 

[Metcalf]

Metcalf!
I like your design. Agree that it needs to stay put under non extreme movement.
Your block is quite large though. How about this idea:
- Since the sides by the soft-shackle does not need to be very ridgid,
- If you make the block in a "U" shape and use a hook and loop to keep each "leg" in place,
- You could then "reverse" the "U" onto/ into the ring for storage, maybe even have it "clip/snap" in for safe keeping.
How flexible can you make those legs on your 3D printer? Is the plastic brittle or are there softere materials available to print?

My block is rigid to help lower the bearing/bushing load on the soft shackle where it wraps around the ring. If the soft shackle is attached to something with a smaller D/d ratio you can get a higher friction rub area on small radius on the OD edge of the ring. The block takes a fraction of the load because of the force vector, but lowers the bearing load and wear on the soft shackle.

You could print in a softer material, but I prefer a fairly strong material for this. I am most likely going to do PETG with a thick shell and a high fill. That will make the legs almost solid. I've been using this quick PLA thin wall 20% infill version for testing with zero issues for a few weeks now.

There are some neat things going on with the strap that I am not sharing just yet. Once side stays attached and locked in place while you work on the other side. This doesn't require 3 hands. I am going with a 24" long soft shackle for my own package. That will give you a bit more spare to attach more things.

The block isn't really that big? It has to be about this size to allow locking the strap into place with the legs so things can't fall apart. It doesn't weight anything. I just store it as an assembly now, but I have an improvement for that when I get my own ring design going. Right now I am using the All-Gear version because it is the most affordable on the market at about $50. The design isn't perfect, but it is pretty good. I made some 'textbook' improvements as suggested by rope manufacturers and simplified a few things. I hope to match their price.

 

[Vinman]

I’ve used mine a few times now and there is absolutely no marks on it at all, not from the soft shackle or the winch line running around the pulley portion.

 

[Vinman]

Without doubt, every time a new product hits the market, there is a hundred reasons why it won’t work

 

[Kruse]

This "ring" system will work just fine as long as people use it within designed parameters.
There is a lot of strength in this ring when forces are in compression.
I do not know how strong it would be if people would try to use it in a pull as you could a normal shackle.
(Pulling from the center in two opposite directions)
May still be quite strong, but I have seen no data on this.

 

[Vinman]

Its not designed to be used in a way where it can be pulled apart, its designed to replace the snatchblock. I wouldn’t trust any piece of aluminum in a scenario where it could be pulled apart. When used as designed, if it does fail, the ropes are still connected.

 

[DaveInDenver]

I'm not a sailor, but isn't that how these low friction rings are sometimes loaded when placed on the jib?



Which I presume ends up looking like this actually rigged?





But perhaps the key is in how you position and tie the twing (in that example) or inhauler to support the ring? Sailing is a mystery to me, absolutely fascinating black magic as it is, with the best words.

 

[Vinman]

Here’s a demo of how they are used in a recovery situation

 

[Low_Sky]

Always wondered what sort of anodised surface is on those things and if any sort of low friction coating over that.
Then what happens when that/those coating wears thru.

I wonder if there are any other applications where dirty synthetic ropes slide over machined anodized aluminum surfaces under load?

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[DaveInDenver]

Thats groovy. But a legitimate ’ExPo Guy knows sails on small vessels dont apply thousands of pound tension upon such riggings.

I had to look it up. Calculating sheet loads. That's what she said.

https://www.riggingdoctor.com/life-aboard/2015/11/18/calculating-loads

A 400 sq-ft jib in 25 MPH wind puts a bit more than 1,000 lbs of force on the rigging. Danged trig. I had no idea. It's all apples to squirrels, sailing is so interesting. I suppose all of this would come into play on a 3 hour tour, though. That sail in a 74 MPH would test 9,500 lb rigging.

 

[Metcalf]

Just wait until dirt get embedded in its shackle rope.
Anyway, the one I handled had a very smooth almost slippery nice finish. For limited use its intended for, even with mild dirt should last a long time.

Pretty easy to wash that stuff every few months. Take care of your gear, your gear takes care of you.