SWL guide to standing rigging

[Roy M]

I need an on-line source for the safe working loads and breaking strength of 1 X 19, 304 SS, rigging wire, specifically 1/4" and 5/16". Any help appreciated. Thanks.

[FrankZ]

When I was looking for the same basic thing I did a google search and found it varies slightly by different manufacturers, but if you do a quick search I am sure you will find numbers that make you feel comfortable. I chose to use a lower average number for mine in case some were more optimistic than they should be.

[David M]

A safe working load (SWL) will varie with the application. SWL is partly a function of the wires breaking strength and partly of the function of its application. SWL is usually a percentage of the breaking strain. So you really need to find out what the breaking strain of that wire is and the percentage they are using to determine their maximum SWL.

SWL for a given wire like for standing rigging might be different for a SWL for something that might receive shock loads (like some running rigging), severe wear and tear or is subject to corrosion. For severe service you would want to reduce the SWL from the manufacturers stated breaking strain and below their maximum stated SWL.

I'm thinking that what you really want to know is the breaking strain, the percentage they are using for SWL and the manufacturers maximum stated SWL and then reduce the SWL to suit your application.

[David M]

I just read what I wrote and it is confusing at best. In a nutshell, the SWL for the application may be less than the manufacturers stated SWL for the wire itself. Never exceed the manufacturers stated SWL. If you are not certain, then consult with a very experienced rigger or a certified naval architect.

[Roy M]

Good grief, guys! Please, I'm not asking for a lecture, I just don't have my rigging book handy with the simple data. That's all I'm asking for. Is there anyone with a link? Thanks, Roy

[Weyalan]

Don't have ready access to 1x19 304 data handy, but typically

316 1x19
1/4" 7100 lb breaking
5/16" 10200 lb breaking

302 1x19
1/4" 8200 lb breaking
5/16" 12500 lb breaking

Souce: Harken catalogue 2005; Table of typical rigging breaking strengths

[Ziggy]

Originally Posted by Roy M

I need an on-line source for the safe working loads and breaking strength of 1 X 19, 304 SS, rigging wire, specifically 1/4" and 5/16"

See Rigging only home page for breaking strengths. SWL is usually taken as 15% to 25% of the breaking strength.

Also, http://www.loosco.com/ has more technical data than you probably want.

[Roy M]

Now we're cookin'! Thanks guys!

[Fard12]

[quote=Ziggy;187859]See Rigging only home page for breaking strengths. SWL is usually taken as 15% to 25% of the breaking strength.


Not true!
The safe working load is not used in standing rigging. We use a safety factor. This will varies form wire to wire on a boat.
eg A V1 wire will be around 2.5 to times the design load. And unless you have software or are an engineer you will be hard pressed to work out the design load for the individual wires on your yacht. If you are using a safe working load to size your wires I suggest that you get a professional to size the wire for you.
Cheers

[GordMay]

1x19 S/S (316) Wire Breaking Strengths from Rigging Only:
http://www.riggingonly.com/08wire.01.jpg

1/4" - 7,489 Lbs.
5/16 - 11,860 Lbs