Shackle block working load ratings?

[Cyrus Safdari]

Can someone explain to me how a shackle block that has a 1/4" shackle can have a safe working load rating that is double that the swl of a 1/4" shackle?

Example https://www.garhauermarine.com/block...-60-13-us.html

It comes with a 1/4" shackle.

Now, check out the swl of a 1/4" shackle from Wichard
https://www.apsltd.com/d-shackle-1-4-pin.html

[Wotname]

Good question, maybe different materials or style of manufacture or dodgy numbers. I note that Garhauer Marine doesn't rate their individual shackles .

Perhaps ask them for the SWL of their shackles.

[Cyrus Safdari]

Garhauer replied that their website was in error, that this was a 5/16th shackle block

I measured the clevis pin to be 19/64 which is indeed about 5/16th

The shackle bow material is slightly rectangular, not round. The "inside" diameter of the saddle was 15/64 and the "outside" diameter was 9/32 -- these are both pretty much 1/4".

Garhauer stated that they measured shackles by the pin diameter; I was always under the impression it shackles were measured by the bow diameter:

Shackles are sized according to the diameter of the bow section rather than the pin size.
https://www.ccohs.ca/oshanswers/safe.../shackles.html

In any case I replaced the shackles with ones that were true 5/16th size

Photos and more at
Sailing Whimsy: Safe working loads of shackle blocks

[coopec43]

Cyrus

You may be interested in this article.


Do you know the difference between SWL / WLL / MRC and when they should be used?

https://asseteng.com.au/do-you-know-...hould-be-used/

[Cyrus Safdari]

Interesting but the term SWL continues to be used commonly

[rmlarson1098]

Originally Posted by Cyrus Safdari

Garhauer replied that their website was in error, that this was a 5/16th shackle block

I measured the clevis pin to be 19/64 which is indeed about 5/16th

The shackle bow material is slightly rectangular, not round. The "inside" diameter of the saddle was 15/64 and the "outside" diameter was 9/32 -- these are both pretty much 1/4".

Garhauer stated that they measured shackles by the pin diameter; I was always under the impression it shackles were measured by the bow diameter:



In any case I replaced the shackles with ones that were true 5/16th size

Photos and more at
Sailing Whimsy: Safe working loads of shackle blocks

It's true, shackles are always 'sized' according to pin diameter. The 'bow' part is usually called the 'bell', if anyone is interested. But I called it as bow for the first 10 years or so of my rigging career. That Garhauer doesn't stamp a SWL is odd. Crosby shackles (Made in USA) always offer the 'Safe Working Load'.