Any theories on what caused this?

[OperationROL]

Wow! This ruins a day. I hope the dealer will let it get fixed under warranty.

 

[Britboater]

So if my articulating keel gets damaged, I might get water ingress into my hull, I can't see Yamaha letting that happen .

 

[octavio3311]

That is a major bummer.
As others have mentioned - it would think it was a strike from underneath.

 

[swatski]

I'd definitely want to get my eyes on the through bolts in the inside of the hull. I think there are 2 or 3 and they are clearly visible from the clean out try "hatch port". I'd be looking to see if the bolt head on the lowest one is still attached, or pulled into the fiber glass....

I agree...looks like a bottom strike to me....probably wouldn't have had to have been a big one....just the weight of the boat sitting on the keel when backed into a beach, and a small wave....and thunk...half the boat weight dropped onto the keel...

My thoughts exactly. Check those thru bolts. I bet you those are okay though.
As @Britboater said, the drain opening would not be compromised as the whole "rudder" thing, I mean articulating keel, is just a bolt-on part.



(never mind the 3 small holes in the embedded aluminum plate on the left - those are for my backup bilge pump install, not from factory)
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[swatski]

I would think that this overall design is an intended (and very smart) feature of the articulating keel.

I would think the rudder is deliberately made of weaker material to become sacrificial, in case of an impact.

This reminds me of similar "design philosophy" for motorcycle steering bar brake/clutch levers (which usually have break-apart notches molded in).

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[Murf'n'surf]

Since the rudder looks like it got pushed to the rear, I think it was hit by something at speed like a log or partially submerged chunk of debris. Or.... it's possible it got banged on the asphalt/concrete apron going in or out of a gas station.

Is the bottom of the rudder roughed up?

 

[druppert]

A guess based on experience I'd say it's not from a strike but a casting defect. The reason I say that is because I have a really steep driveway & I drag the rear tip of my keel about every 3-4 times out when I don't get the angle just right. There's several gouges in my driveway & some scrapes on the keel but no structural damage (so far). It seem unlikely to me that you could have hit something in the water to damage it while I drive the keel into concrete without similar effects.

 

[zipper]

So many good points to agree with. I agree with designing in weaker areas to break first under unforeseen loads, but that would not be the place to do it, maybe the hinge pin or the actual rudder section of the assembly. Striking the rear of the articulating keel and pulling it away as it appears to be would be first guess, but no damage to bottom of "keel" was mentioned. Leading me to think there was a flaw during the casting process that revealed itself while "beating on his boat pretty hard" and you may need to find a metallurgist to prove it to Yamaha for a warranty claim. Unless they are aware of this problem, during their trials testing of launching from waves in heavy seas. Think they would have fixed those weak points though. Referring to the video of the AR tower test on a 21' yamaha years ago.

 

[Julian]

I think they should put more of a curve into the leading edge of the rudder, the way it is now if prime for catching things on it.

 

[buckbuck]

@Brian eilrich Are you out there? We need your input.

Just to be clear, he discovered this prior to us going out. And if it didn't come off with what he did to his poor boat then I doubt it will break off later.

I felt the bottom edge of the rudder and did not feel anything unusual. But I did not look at it.

I believe it will be an interesting conversation between he and Yamaha. Any metallurgy guys on this forum?

 

[Speedling]

@Brian eilrich Are you out there? We need your input.

Just to be clear, he discovered this prior to us going out. And if it didn't come off with what he did to his poor boat then I doubt it will break off later.

I felt the bottom edge of the rudder and did not feel anything unusual. But I did not look at it.

I believe it will be an interesting conversation between he and Yamaha. Any metallurgy guys on this forum?

My father in law runs a machine shop and I can show it to him, but without the piece being in his hands, he probably couldn't figure it out. I've seen him weld pot metal before with impressive results, but I am sure it's some aluminum version of something knowing Yamaha.

 

[jameskeller76]

He hit something or backed into something almost looks more likely since the hull looks fine. That whole piece on the 240 looks plastic.never really felt it to see if it was something different.

My exact thought, backed into a pier or something.

 

[jcyamaharider]

Oh man!! Sorry to see this. Hopefully Yamaha gets it taken care of quick. Looks like a bad casting or like someone else said, underwater debris.

 

[skrip345]

Is it possible a small pebble, or other piece of debris could have been stuck in the action part of the hinge? Its a long shot but if something was floating around and found its way into the crevice of the hinge, then forced to turn with the steering wheel it would/could produce an outward force...that combined with a casting flaw? With the right leverage it wouldn't take much to pop that casting, could've felt like a light bind in the steering.

 

[Noko]

based on the markings and careful measurements....perhaps this:View attachment 55811

I don't know how many times I've had this happen. Thank God for the YES warranty.
Funny, every time we go out, my wife says, "You are going to need a bigger boat!"