Water Pickup

[SnoC653]

If you think they might have been 7075 pore a little ammonia on the plate, if it turns black there's a lot of zinc and is most likely 7075.

Well they aren't 7075 then. I put ammonia and soaked the area between the turnbuckle pads and no black. The plates were painted black and you can see the doubler was also. Paint is worn off/polished off the doubler.

Here is a picture of the crack itself. You can see where it ran along the pressure line from the turnbuckle pad and then started heading to the front edge. This is the bottom of the plate.

[WESTERNAERO]

We're they painted or were they anodized. Anodize fades in the sun like I'm seeing there, and it won't let ammonia or a mind acid react with the zinc. I am seeing a white chaulking corrosion in the c/s holes. That crack looks like the plates saw some trauma and hole to hole was the weak link.
It's kinda funny my old hardware on my boat half of was made with 7075. There's a lot of chaulking on some of the parts. Kinda like these old boat builders were just that and racers on the side. Seems like they would just go down to the local material supplier and grab all the rems of aluminum that were available. Because aluminum is aluminum , right?

[SnoC653]

We're they painted or were they anodized. Anodize fades in the sun like I'm seeing there, and it won't let ammonia or a mind acid react with the zinc. I am seeing a white chaulking corrosion in the c/s holes. That crack looks like the plates saw some trauma and hole to hole was the weak link.
It's kinda funny my old hardware on my boat half of was made with 7075. There's a lot of chaulking on some of the parts. Kinda like these old boat builders were just that and racers on the side. Seems like they would just go down to the local material supplier and grab all the rems of aluminum that were available. Because aluminum is aluminum , right?

I figured it was paint because it didn't cover the edges in the middle. I also sanded an area down and rechecked with the ammonia, no color change. There was definitely a lot of flex going on where they cracked, the doubler has metal transfer from rubbing and a small crack forming as well. The new plates will be 6061 T6 if that is what is prefered these days. I even considered going to stainless since the pedal will have some type of assist on it for racing.

[gn7]

I figured it was paint because it didn't cover the edges in the middle. .

That's because who ever made the plate tried to use a single plate and found out they couldn't get the boat to handle for shit and cut the plate in half.

[ogshotgun]

Well they aren't 7075 then. I put ammonia and soaked the area between the turnbuckle pads and no black. The plates were painted black and you can see the doubler was also. Paint is worn off/polished off the doubler.

Here is a picture of the crack itself. You can see where it ran along the pressure line from the turnbuckle pad and then started heading to the front edge. This is the bottom of the plate.

i have seen this exact issue on a boat before in the exact spot...it was damaged from a floor jack lifting the back of the boat up to service the rudder... no need to re invent the wheel .. its metal its old worn out .. replace it.. if the tire on your car gets a slice do you replace the tire or re invent the wheel ???

also that looks like type III hard anodizing also ... fades bad in the sun will lose the color but not the coating and its i believe aout 2-3 thousands thick

[SnoC653]

This may or may not help, but I've never seen a Biesemeyer K boat with 8 turnbuckles. I've never even seen an NRKA Biesemeyer with 8 turnbuckles.


I think the boat was backed into something or rear ended causing the plate to break.

Don't worry, If I run the boat in the NRKA I'll add turnbuckles between each pair, that should make my boat two turnbuckles faster than your boat and that much harder to get off the trailer and into a race.

i have seen this exact issue on a boat before in the exact spot...it was damaged from a floor jack lifting the back of the boat up to service the rudder... no need to re invent the wheel .. its metal its old worn out .. replace it.. if the tire on your car gets a slice do you replace the tire or re invent the wheel ???

also that looks like type III hard anodizing also ... fades bad in the sun will lose the color but not the coating and its i believe aout 2-3 thousands thick

Guaranteed that isn't a result of jacking the boat. The miniature fissures show repeated stres, as well as the crack traveling over time. What you can't see is that there is also transference from the plate vibrating against the doubler. That doesn't happen with a one time event.

As for Anno or paint, hard to say, but the bottom shows no wear wich leads me to believe it has been re-painted or whatever it is.

[ogshotgun]

Don't worry, If I run the boat in the NRKA I'll add turnbuckles between each pair, that should make my boat two turnbuckles faster than your boat and that much harder to get off the trailer and into a race.



Guaranteed that isn't a result of jacking the boat. The miniature fissures show repeated stres, as well as the crack traveling over time. What you can't see is that there is also transference from the plate vibrating against the doubler. That doesn't happen with a one time event.

As for Anno or paint, hard to say, but the bottom shows no wear wich leads me to believe it has been re-painted or whatever it is.

if you take the metal and hit it with a wire wheel .. if its anodized there will be a strange smell .. thats how i know for sure

[WESTERNAERO]

That's anodized

[WESTERNAERO]

Hey Sno, I'm not sure if you know this, I thought this would be kinda common knowledge but, make sure when you order your new material the grain direction is going with the short length of the plates. Or linear with the boat maybe is a better way to say it.