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Loads on an adjustable backstay

Jan 2, 2013
66
Catalina 22
Hello All,

As one of my upgrades this winter, I am adding an adjustable backstay. It is the 6 part tackle type. I have most of the blocks/hardware purchased. I also purchased a backstay replacement kit from another owner that was new, but never installed. D2160. I have never paid much attention to the "loads" that get exerted on rigging in different wind conditions, and since it is -35 F wind chill today, that is what I am researching.
One specific question would be the working load (WL) for the wire backstay, and also the WL for the shorter wire that is attached to stern on one side, and the tackle on the other.

I am trying to determine the weakest link in the completed system.
I also am not sure of the 10' wire type (1/8 -7 x 7?)
also not sure of the wire type of the backstay (1/8 - 1x19?)

Any feedback would be appreciated
 
Jul 7, 2004
6,012
Hunter 30T Cheney, KS
Do other C22 owners find an adjustable backstay useful?
I put one on my Mac. Not because I found it useful but because I was new and I could.
 
Jan 2, 2013
66
Catalina 22
forgot to mention, that the weakest point that I can estimate right now is the 10' wire.
if it is 1/8 x 7 x 7 stainless, Suncor shows a WL of only 272# which seems light to me.
 
Aug 10, 2014
314
Catalina 22 9874 Newberg, OR / Olympia, WA
forgot to mention, that the weakest point that I can estimate right now is the 10' wire.
if it is 1/8 x 7 x 7 stainless, Suncor shows a WL of only 272# which seems light to me.
If I understand correctly, that 10' wire is the 2:1 cascade, so each leg should only get ~1/2 of the full backstay load (increased slightly by the angle between the legs, but that angle is pretty acute, so not a huge increase).

Others might explain to me how and why I was stupid, but I replaced my (kinked and worn) backstay and cascade wire with Amsteel. I used 5/32" for the stay (working load ~800 lbs) and 3/16" (WLL >1k lbs) for the cascade (the latter not for increased strength; just because I had some 3/16" on hand). For standing rigging, Amsteel would creep too much, and we'd want something like Dux or STS-WR2. But an adjustable backstay is more like running rigging than standing - it's often adjusted, so we don't need to worry too much about slow creep under tension.

You already have the wire kit, so you probably want to just use it. But perhaps someone will find that useful.
 
Jan 2, 2013
66
Catalina 22
If I understand correctly, that 10' wire is the 2:1 cascade, so each leg should only get ~1/2 of the full backstay load (increased slightly by the angle between the legs, but that angle is pretty acute, so not a huge increase).

Others might explain to me how and why I was stupid, but I replaced my (kinked and worn) backstay and cascade wire with Amsteel. I used 5/32" for the stay (working load ~800 lbs) and 3/16" (WLL >1k lbs) for the cascade (the latter not for increased strength; just because I had some 3/16" on hand). For standing rigging, Amsteel would creep too much, and we'd want something like Dux or STS-WR2. But an adjustable backstay is more like running rigging than standing - it's often adjusted, so we don't need to worry too much about slow creep under tension.

You already have the wire kit, so you probably want to just use it. But perhaps someone will find that useful.
Excellent point about the 2:1 purchase with the V. I am planning on using the kit, but as I said I am always digging for more info than needed for a project.

I guess I still would like anyone to chime in with the load numbers at different wind speeds that a 22 experiences.

Cheers to all of the contributors to this forum, you are the best.