Forestay wire to be 8/32" or 9/32" ?

[macbeth]

Originally Posted by delmarrey

304L is slightly magnetic, 316L is not. Use a strong magnet to test.

Wonderful !! I tried that on my old forestay and a sample piece of known 316 and there was a noticeable difference. Thank you VERY much. Have a beer on me !

it turned out the old 1/4" forestay was 304, so to get the equivalent strength (and a bit more) in 316 I will move up to 9/32".

Again, thanks very much.

CASE CLOSED !!

[wolfenzee]

I just made up all new standing rigging for my boat. The boat was rigged for bluewater and most of the rigging is 1/4", back stay and cap shourds were a little lighter because their main purpose was for flying a large genny off the masthead in light air (head stay is fractional w/running backs). It was suggested to my to use 3/8 for the forestays because of wear from jib hanks, but there was no wear so I decided against that. I used 1/4" for everything for continuity sake (and I got a good deal on wire because I bought a 300' spool....had 32" left over). There is not a problem with wieght aloft as much as windage. I have a tall (45') and very flexible wooden mast so have lowers, intermediates, cap shrouds, head stay (fractional), top stay, back stay and running backs. My boat is 30'
It is hard to say what size you should use, it depends on how big you boat/rig is and how hard you drive it and/or where you sail.

[delmarrey]

Originally Posted by macbeth

Wonderful !! I tried that on my old forestay and a sample piece of known 316 and there was a noticeable difference. Thank you VERY much. Have a beer on me !

it turned out the old 1/4" forestay was 304, so to get the equivalent strength (and a bit more) in 316 I will move up to 9/32".

Again, thanks very much.

CASE CLOSED !!

Actually 304 is stronger then 316, so you'll only be gaining a little bit, if any.

[macbeth]

From what I can find, I believe:

1) The breaking strength of 1/4" 304 wire is 8,200 lbs. (my old forestay)

2) The breaking strength of 1/4" 316 wire is 6,900lbs (weaker than old forestay, so no good)

3) The breaking strength of 9/32" 304 wire is 10,300 lbs (I don't want 304)

4) The breaking strength of 9/32" 316 wire is 9,250 lbs. (better rustproofing and stronger than old forestay)

So you can why I'm going to 9/32" 316 wire, i.e. I get better rust proof wire, and a bit more strength. The latter doesn't really concern me, but the former does.

And you can see why I wouldn't want to go with 1/4" 316 as it would not be as strong as my old forestay.

Once again THANKS !!

[wolfenzee]

Originally Posted by delmarrey

Actually 304 is stronger then 316, so you'll only be gaining a little bit, if any.

But 316 lasts longer

[delmarrey]

Originally Posted by macbeth

From what I can find, I believe:

1) The breaking strength of 1/4" 304 wire is 8,200 lbs. (my old forestay)

2) The breaking strength of 1/4" 316 wire is 6,900lbs (weaker than old forestay, so no good)

3) The breaking strength of 9/32" 304 wire is 10,300 lbs (I don't want 304)

4) The breaking strength of 9/32" 316 wire is 9,250 lbs. (better rustproofing and stronger than old forestay)

So you can why I'm going to 9/32" 316 wire, i.e. I get better rust proof wire, and a bit more strength. The latter doesn't really concern me, but the former does.

And you can see why I wouldn't want to go with 1/4" 316 as it would not be as strong as my old forestay.

Once again THANKS !!

I'm not disputing the use of 316, just stating facts. Don't know where you got your numbers from but this 7 X 19 Aircraft Cable seems to be the norm.

.

[wolfenzee]

What sort of rig do you have, what size boat and what type of sailing do you plan on where and/or in what conditions. These are all important factors.
A surveyor called what I have on my boat ""beefy"......but it was rigged for bluewater sailing by someone that likes to push their boat hard.
When I replaced the standing rigging I made sure it matched (and in some cases exceeded what was their). But I am preparing for ocean passages and I don't want to have to worry about the rig when the wind pipes up (my boat is too much fun in high winds to have to worry about my rigging)

[Ziggy]

Originally Posted by delmarrey

I'm not disputing the use of 316, just stating facts. Don't know where you got your numbers from but this 7 X 19 Aircraft Cable seems to be the norm.

.

Usually standing rigging is made from 1x19 cable. At least in the U.S., most is sourced from Loos&Co. You can find their specs for the 304 and 316 cable here

[Adelie]

Originally Posted by delmarrey

I'm not disputing the use of 316, just stating facts. Don't know where you got your numbers from but this 7 X 19 Aircraft Cable seems to be the norm.

.

7x19 wire is used for items that will bend a lot, so on a boat it would be used for running backs, checkstays, a removable forestay (for a staysail) or for steering wheel cables. 7x7 may also be used for these things.

1x19 is the normal construction for standing rigging.

[wolfenzee]

Originally Posted by Adelie

7x19 wire is used for items that will bend a lot, so on a boat it would be used for running backs, checkstays, a removable forestay (for a staysail) or for steering wheel cables. 7x7 may also be used for these things.

1x19 is the normal construction for standing rigging.

My mast is Sitka Spruce, laminated and cambered, designed to flex ( the tuning process creates a significant, easily adjustable bend) and the rig is a "low tension rig" designed to use 7x19, as opposed to modern "high tension rigs" with aluminum mast which use 1x19, rod or other low stretch materials gain alot of their strength from compression.
A rigger who was used to "modern" high performance rigs could not wrap their mind around mine which was designed 75years ago using different materials as well as physics.

[delmarrey]

Originally Posted by Ziggy

Usually standing rigging is made from 1x19 cable. At least in the U.S., most is sourced from Loos&Co. You can find their specs for the 304 and 316 cable here

Wow! My mistake!
I wasn't looking at the number of wires. It seems to make a big difference. I would think aircraft wire would be of a higher strength.

A 1000# difference is a lot better then 300#