Rudder Toe-In?

[Avenger]

Toe-in. You're looking straight down at the rudders and the top of the drawing is the front of the boat.

That is actually to scale, so you can see that there's quite a bit of toe. Also, the 65.747 dimension represents the rudder arms and tie-rod.

I created that drawing to validate the dimensions I was using to fabricate a new tie-rod. Since I was doing the fabrication in my shop and the boat was in the water I couldn't just go out with a tape measure to figure out dimensions. This way I could create the elements i.e rudders and rudder arms, lay it out like the original, and verify that my real tie-rod length matched the drawing. Next I re-configured it to get the correct toe-in and the program produced a dimension for the new tie-rod.

 

[Brian Degulis]

I think Trojan is correct but he's explaining it in a very confusing way. The way I read it Hat is saying on mikes boat that the leading edge needs to be 3/4" to 1 1/2" out or in from the trailing edge. That's on the same rudder in relation to the boats centerline so you can't measure the leading or trailing edges from rudder to rudder because there is more blade behind the rudder shaft than there is in front of it. So if you wanted a toe in of say 1 1/2" and you simply measured from the leading edge of the stb rudder to the port rudder then measured trailing edge from port to stb you would not have the correct toe in. It would have to measured from a line parrellel to the keel or calculated ahead of time to get the dimensions from rudder to rudder.

Brian

 

[Avenger]

Well, he's sure confusing the daylights out of me. Your explanation of the difference being between the leading edge and trailing edge of the same rudder I could accept. It certainly wouldn't result in the kind of total toe that's shown in my drawing. However, as I'm reading Bill's explanation he seems to be saying that it is measured from the leading edge to the center of the rudder shaft. That will produce the kind of toe that the drawing shows which I hope we can all agree is too much.

 

[Brian Degulis]

Well, he's sure confusing the daylights out of me. Your explanation of the difference being between the leading edge and trailing edge of the same rudder I could accept. It certainly wouldn't result in the kind of total toe that's shown in my drawing. However, as I'm reading Bill's explanation he seems to be saying that it is measured from the leading edge to the center of the rudder shaft. That will produce the kind of toe that the drawing shows which I hope we can all agree is too much.

]
Center of the shaft has no meaning to me. The leading and trailing edge of the same rudder should be measured from a line that runs parallel to the keel. The dimension of toe in is the difference between those measurements. When both rudders have been done this way then you can measure from one rudder to the other and save that dimension for future reference. This is based on the exact explanation that Mike got from Hat. It's possible they explained the procedure wrong it would have to be verified with them. On the boats we build we simply give the customer the difference from trailing and leading edges on both rudders because it's much easier to do that way.

Brian

 

[Nonchalant1]

Brian,

OK - So if I measure the distance between the trailing edge of both rudders and then the distance between the leading edge of both rudders, the trailing edge measurement should be about 2 inches longer? Also, since the rudders are shaped, I'd take the measurements about at the middle of the rudders vertically.

Since both rudders move in unison and stay toed about the same anywhere near centered, for purposes of measuring it shouldn't matter if the wheel is set exactly to parallel with the keel as long as it's close to centered. I'd just use my autopilot center mark, which does keep the boat going on a straight line.

Thanks again,

Doug

 

[34Hatt]

Well, he's sure confusing the daylights out of me. Your explanation of the difference being between the leading edge and trailing edge of the same rudder I could accept. It certainly wouldn't result in the kind of total toe that's shown in my drawing. However, as I'm reading Bill's explanation he seems to be saying that it is measured from the leading edge to the center of the rudder shaft. That will produce the kind of toe that the drawing shows which I hope we can all agree is too much.

Derek I followed it the same as you Bill is confused or making it confusing!!

This is a simple thing at least that's what I thought until reading some of this Stuff Yikes!!!!!

Mikes email from Hatteras is the way I always thought of it and it spells it out in simple words!

 

[Brian Degulis]

Brian,

OK - So if I measure the distance between the trailing edge of both rudders and then the distance between the leading edge of both rudders, the trailing edge measurement should be about 2 inches longer? Also, since the rudders are shaped, I'd take the measurements about at the middle of the rudders vertically.

Since both rudders move in unison and stay toed about the same anywhere near centered, for purposes of measuring it shouldn't matter if the wheel is set exactly to parallel with the keel as long as it's close to centered. I'd just use my autopilot center mark, which does keep the boat going on a straight line.

Thanks again,

Doug

No if your going to use the dimension that Hat has given to mike then you must measure from a line parelel to the keel to the leading and trailing edges of the same rudder not from one rudder to the other. Hat is saying they want the leading edge 3/4" to 1 1/2" outboard of the trailing edge that dimension is on the same rudder not from one rudder to the other. Because the rudder shaft is not centered for and aft on the rudder blade there would be no way to get the dimension measuring one rudder to the other.

IMHO the amount of toe in is not at all critical. I think you could go from rudder to rudder get about a 2" diffrence from front to back and you would be just fine. I just read the post and thought that Trojan was correct but explained it in a confusing way. Looks like I'm not doing any better he did LOL


Brian

 

[Avenger]

Poor Horsey Won't Get Up.

Okay, here's my diagram of how I'm understanding this:

A) Bill's method: A line through the center of the shaft parallel to the keel or centerline, with the leading edge of the rudder one inch closer to the centerline.

B) Brian's method: the leading and trailing edges of the rudder one inch apart from each other in relation to the centerline. As far as I can see this leads to 2" of toe when you measure the rudders against each other.

C) My method: the trailing edges one inch further apart than the leading edges.

By literal interpretation of Hatteras' wording Brian is right. Since they used singular "edge" instead of "edges". However, IMHO, since the two rudders work together as a system using toe to load them is only relevant when considering them as a pair. i.e. a single rudder with toe isn't toed at all, it's just turning the boat.

Anybody please feel free to jump in here and clear this up if they have a different view. My arm is getting tired of swinging at this horse.

While I'm awaiting replies I'll be polishing my micrometer for the macerator vs vacuflush contest.

 

[SKYCHENEY]

I agree completely. Brian's method is technically correct based on the wording from Hatteras, but I would use your method were I adjusting mine. That may, in fact, be what Hatteras was saying(depending on how you interpret it). It takes very little toe to load the rudders and the more you have, the more drag you incur.

 

[MikeP]

When I received Hatts email, I understood it as diagram c though the toe could have been in the opposite direction per them - I adjusted it per C.

 

[Trojan]

I would agree that if the toe is the difference between the leading edge and the trailing edge. It would be real easy. The drawing that I had only dealt with the leading edge and the rudder shaft center line. This is why I say measure the shaft center line. Subtract the amount of toe you want and set the leading edge. I was trying to explain the changes that could happen if the shaft offset dimension changes or the ratio changed. As the shaft offset changes so goes the trailing edge.

Just eyeball the damn rudders and let them go.
As long as there is water pressure on the entire blade and you have toe in. It should be OK. Just make them as straight as you think you can get away with. Your not going to have any tire ware . I think everyone is over complicating things.

BILL

 

[Traveler 45C]

So diagram C is Toe-in? Why "In" if the trailing edges are out?

Sorry for the elementary question, just trying to understand.

 

[mobilemn1]

Because the leading edge of the rudder is pointed inward.....Same as with aligning the front end of a car to prevent drift in the case of the car

 

[Avenger]

Your not going to have any tire wear . I think everyone is over complicating things.

Exactly, there's no ackerman geometry in a fluid medium. (For those who aren't familiar, it's a automotive steering engineering term.) My concern was that, in my case, the ratios led to a lot of deflection and speed loss, so I didn't want our other members to build a brake.

So diagram C is Toe-in? Why "In" if the trailing edges are out?

As Daryl said, it's a term used in wheel alignment. The best explanation I can give you is to look at the rudders or tires as a pair of feet. Your toes are in the front and if they're closer together you're TOED-IN.