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 Boat Design Forums Forestay Load Calculation for Toggle

#1
02-28-2006, 09:58 PM
 JSBKC Join Date: Feb 2006 Rep: 10 Posts: 2 Location: Kansas City

I've been unsuccessful finding a website to calculate the rig loads on my forestay (O'Day 34, ~ 600 sq sail area, 9/32 wire). Specifically, I'm trying to determine if an Eye Jay Toggle (WestMarine # 453324 1/2" pin - rated at 3400 lbs) is strong enough. Any help greatly appreciated. -
#2
02-28-2006, 10:10 PM
 bhnautika Senior Member Join Date: Feb 2006 Rep: 566 Posts: 602 Location: australia
Size fittings to a bit above the breaking load of the wire, 9/16 about 8000lbs
#3
02-28-2006, 10:34 PM
 RHough Retro Dude Join Date: Nov 2005 Rep: 724 Posts: 1,641 Location: BC Summers / Nayarit Winters
Quote:
 Originally Posted by JSBKC I've been unsuccessful finding a website to calculate the rig loads on my forestay (O'Day 34, ~ 600 sq sail area, 9/32 wire). Specifically, I'm trying to determine if an Eye Jay Toggle (WestMarine # 453324 1/2" pin - rated at 3400 lbs) is strong enough. Any help greatly appreciated. -
The diameter of the hole in the forestay chainplate determines what will work. For 9/32 wire the pin should be 1/2" diameter.

Eye-Jaw toggles are built to carry the same working loads as the pin.

If the pin fits properly, the toggle should be fine.

I couldn't find the 3400# rating for that toggle. The rated break strength of 9/32 1/19 type 302/304 wire is about 10000# or about 8500# for type 316. If 3400# is the safe working load, it is in the 30-40% of breaking strength range. I can't imagine an Alexander-Roberts 1/2" toggle being rated at 3400# breaking strength.
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#4
02-28-2006, 10:38 PM
 JSBKC Join Date: Feb 2006 Rep: 10 Posts: 2 Location: Kansas City
Yes the Eye-Jaw toggle has 1/2" pin just like the forstay. The 3400 lbs load seems low to me.
#5
02-28-2006, 10:53 PM
 RHough Retro Dude Join Date: Nov 2005 Rep: 724 Posts: 1,641 Location: BC Summers / Nayarit Winters
Quote:
 Originally Posted by JSBKC Yes the Eye-Jaw toggle has 1/2" pin just like the forstay. The 3400 lbs load seems low to me.
That has got to be a SWL number, not a breaking load number. I've never seen a eye-jaw toggle break before some other part of the assembly. I use bits from A-R all the time, no problems with the quality.
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I have not failed. I've just found 10,000 ways that won't work.
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