Double Jaw Standing Rigging Toggle Replacement

[Boatguy30]

Those are padeyes not chainpates. All manner of corrosion possibilities on 42 y/o stainless 18-8 screws. Wouldn't surprise me at all if the rigging was that old.

Perhaps replace just the uppers this season.

[Sailor_Grant]

I thought they were just called deck mounted chainplates because they were attached to wire.

If I were to replace the bolts, should I use Stainless?

Maybe just replacing the uppers is a good idea.

[Disailor]

Sailor Grant: Long narrow chain plates rely on the shear strength of several bolts holding them in place. Your setup relies on the 2 machine screws in tension. Picture the threaded section as a bellows then add tension, release, tension, release etc. I would be concerned about those screws & replace them with silicon bronze FH machine screws with long un-threaded sections where they pass thru the deck.
If the original rig required 0.5" pins it's because that's the pin diam that has the required strength. Going smaller defeats/reduces your safety margin.
If reaming the padeye to the correct pin size does not violate the design specs for a 0.5" pin (0.5" either side of the pin hole as well as from pin hole edge to end of tang, that would be the way to go. If you can't then replace the padeye with welded stainless (assuming you can't find a larger size bronze padeye).
Replacing the turnbuckle with an open body & proper size pin hole is more than wise.
Oh, and butyl tape for bedding (https://marinehowto.com/).

[Dougtiff]

There are rigging Bushing's, but i would replace the Toggle's, as they are deformed, and yes at some point go with OPEN turnbuckle's, then replace the wire at a later date. PS, i would not drill out the chain plate.

[Sailor_Grant]

Originally Posted by Disailor

Sailor Grant: Long narrow chain plates rely on the shear strength of several bolts holding them in place. Your setup relies on the 2 machine screws in tension. Picture the threaded section as a bellows then add tension, release, tension, release etc. I would be concerned about those screws & replace them with silicon bronze FH machine screws with long un-threaded sections where they pass thru the deck.
If the original rig required 0.5" pins it's because that's the pin diam that has the required strength. Going smaller defeats/reduces your safety margin.
If reaming the padeye to the correct pin size does not violate the design specs for a 0.5" pin (0.5" either side of the pin hole as well as from pin hole edge to end of tang, that would be the way to go. If you can't then replace the padeye with welded stainless (assuming you can't find a larger size bronze padeye).
Replacing the turnbuckle with an open body & proper size pin hole is more than wise.
Oh, and butyl tape for bedding (https://marinehowto.com/).

True, but the tensile strength of one machine screw is 70,000 PSI, source.

Shouldn't I re-rig it with the design specifications, and just find a T Bolt/Toggle setup with a smaller clevis pin? This boat was designed by Carl Alberg and is known to be incredibly strong, I don't want to alter his design specs.

Why replace the padeye? And why with welded stainless? Please refer to this article.

https://missionmariah.wordpress.com/...nplate-design/

[Cheechako]

Originally Posted by Sailor_Grant

True, but the tensile strength of one machine screw is 70,000 PSI, source.

Shouldn't I re-rig it with the design specifications, and just find a T Bolt/Toggle setup with a smaller clevis pin? This boat was designed by Carl Alberg and is known to be incredibly strong, I don't want to alter his design specs.

Why replace the padeye? And why with welded stainless? Please refer to this article.

https://missionmariah.wordpress.com/...nplate-design/

The reality is those two screws appear to be larger diameter than the rigging pin. The rigging pin is in shear stress also which is approximately 60% of tensile strength. I imagine that Cape Dory had it designed properly. It's only a 27 foot boat right?
Not a big fan of countersunk heads in cast material personally. In tension the angled head acts as a wedge trying to tear the cast material apart. But again, They probably thought of that.
"For 316 stainless, the tensile strength is about 84,000 psi, so the shear strength is roughly 50,000 psi. ... In other words, it's approximately 60% of the tensile strength. For 316 stainless, the tensile strength is about 84,000 psi, so the shear strength is roughly 50,000 psi"

[Orion Jim]

Originally Posted by Boatguy30

Those are padeyes not chainpates. All manner of corrosion possibilities on 42 y/o stainless 18-8 screws. Wouldn't surprise me at all if the rigging was that old.

Perhaps replace just the uppers this season.

https://www.spartanmarine.com/chainplates-stemheads

Someone should notify the manufacturer.....

[Sailor_Grant]

Ok, so on further research, it seems that the hole for the chainplate is 3/8 inch and the toggle pin size is 1/2.

I cannot find a toggle with different sizes for the pin and the thread size anywhere, does it even exist?

For example, a toggle with a pin size of 3/8 connected to a T-Bolt with a thread size of 1/2-20?

Why am I unable to find that anywhere?

[roverhi]

If it's a 27' boat 3/8" turnbuckles are more than adequate. Sounds like someone got a deal on 1/2" turnbuckles and used 3/8" pins to match the deck fittings rather than 1/2". Get new 3/8" open body turnbuckles. The way it's set up now will probably work for the life of the boat but I wouldn't chance it.

Good idea to change out the SS bolts just to be sure that there's no crevice corrosion. 316 stainless has less strength than 304 but both are more than adequate for the job. Bronze would be a better fit but weaker than either 304/316. Rebed the deck fittings and fasteners with butyl.

[Cheechako]

Originally Posted by Sailor_Grant

Ok, so on further research, it seems that the hole for the chainplate is 3/8 inch and the toggle pin size is 1/2.

I cannot find a toggle with different sizes for the pin and the thread size anywhere, does it even exist?

For example, a toggle with a pin size of 3/8 connected to a T-Bolt with a thread size of 1/2-20?

Why am I unable to find that anywhere?

Certain manufacturers made turnbuckles with different pin sizes for the same wire size. Made to fit a wide variety of boats. Not sure what you can find today. Maybe someone upgraded the wire size too? What size wire do you have? what does C.D. say the wire should be?
I wonder what style turnbuckles came with the boat?

So....

I'd talk with Cape Dory and find out what's what. It sounds like the PO upgraded the wire size on the boat.

Short of getting everything back to original. ...I would still probably ream out those deck fittings. Not crudely but a pro job. There appears a lot of meat on those fittings. A nicely reamed hole with a smooth surface may be better than original .
or
Talk with a rigger, he may have bins of parts laying around, you may find a couple 3/8" pin toggles he has for that 1/2" turnbuckle, used or new.? Or at least he would know if they ever existed.

Too bad turnbuckles are so damn expensive now days. Nice chromed bronze ones were like $50 wholesale 20 years ago.

[Cheechako]

I question if you want to use Butyl Tape in this application. You dont want water in with the screw. Just a thought.

[Sailor_Grant]

Ah, I would going to wrap it around the conical section of the screw too so it would extrude into that area and fill the void. But I appreciate the concern

[Dougtiff]

As a rigger, i would replace the toggle,as it is deformed,tou can source a toggle with the correct pin size.

[AKA-None]

If you can’t replace the toggles right now can’t you put a slaver in the toggle hole to shim it to 3/8?