Rudder

[Gene Rosson]

The rules prescribe a maximum rudder dimension in two planes. Those are taken to be within the profile or elevation view of the rudder. No specification for thickness or section shape. We could have a fat rudder, a skinny one, one with reflex curves, etc. What is the class position about adding a vortex fence (tip plate)?

I assume that tip plates have been tried before. If so, what was the outcome in terms of rudder function ?

[s vernon]

Gene,

Reread the rule. It does have a limit on rudder width - only as wide as the aft end of the keel. So a narrow end plate is a possibility. But not a wide end plate.

Scott

[Carl]

I just read the new rules we are being asked to vote on.
Section 7.0 rudder lists aluminum or brass.(Model Yachting #139)
Seeing aluminum is not in favor - are we all going to use brass??
Now that should make it heavier.[:0]

[PegLeg]

Carl

Please re read the proposal on rudders. It clearly reads aluminum or brass "inserts" are permitted within the FG or wood rudder. Depending of the width, length and thickness of material used, the insert is most likely to have little or no effect to the weight. Certainly rudders made completely of Brass or aluminum would not be allowed with the proposed rule.

[Carl]

I miss read the insert part.
I was thinking of the rudder shaft material.
Opps.

[Gene Rosson]

Scott;
Thanks for the tip. I must discipline myself to read the rules more carefully. The tip plate notion was only a question, not necessarily an intent. I suspect a narrow plate would not help much if at all. Also it would be more vulnerable.

The other guys are carrying on about rudder shafts. You can use a relatively small shaft, aluminum or otherwise, if you also use a lower bearing bracket. That is to say, a bearing plate installed near the bottom of the rudder. I have seen these and it makes a heap of sense because a 5 plus inch cantilevered load needs a fairly substantial shaft and a very secure shaft housing.

A rigid rudder installation may be more important than we have yet proven. If the rudder oscillates or quivers it is sure to set up some unwelcome drag while diminishing steering effect. Big boat sailors will be familiar with rudder quiver that sometimes reaches an amplitude that vibrates the whole boat. At the least, it makes a lot of noise. Such boats are famously slow.

Gene

[bogordoug]

But isn't the rudder shaft also an insert in the rudder? Although it extends beyond the rudder, it is still an insert. I would guess that maybe a lot of rudders (with carbon, stainless steel, or titanium shafts) may need rebuilding after the rules are promulgated/approved. Which leaves us with soft bendable rudder shafts.

Doug Hale

[Rick West]

The proposed rewrite of the class rules, which has been posted for months, was not a proposal for change but to update the first three sections to current class operations and to integrate interpretations going back many years by class secretaries. This has been stated from the outset of the project. The project was not lightly taken or to inject rule changes outside of proper process.

The allowance to place metal inserts in a rudder fabrication of wood and/or fiberglass was not published but known. This was to strengthen the structure and particularly along the trailing edge of the rudder to allow fairing of the surface where it could be brittle. The mention of specific metals may not have been needed initially but because it was the inclusion was as you see it and with use of the word “inserts.â€