Daggerboard position

I've got the old style wooden centerboard (1973 Sunfish) and am wondering - which edge of the board should face forward? The edge that's straight all the way to the bottom, or the edge that curves near the bottom?

Thanks.

The edge that is straight to the bottom should face forward, assuming that is the thicker edge. The thin edge is aft. It's like an airplane wing, thick leading edge, thin trailing edge.

I just checked, and neither my daggerboard nor my rudder are foil shaped. Their edges are rounded but they are otherwise flat.

Any pictures I've seen show the edge that is straight all the way to the bottom facing the front of the boat, just as you suggest. To me, it just looks backward.

Maybe the daggerboard I have was a homemade replacement?

Randy Ricchi said:

I just checked, and neither my daggerboard nor my rudder are foil shaped. Their edges are rounded but they are otherwise flat.

Any pictures I've seen show the edge that is straight all the way to the bottom facing the front of the boat, just as you suggest. To me, it just looks backward.

Maybe the daggerboard I have was a homemade replacement?

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The long edge goes forward as the pictures show. The objective is not to look streamlined, but to generate lift. The long edge fwd generates more lift.

BB

beldar boathead said:

The long edge goes forward as the pictures show. The objective is not to look streamlined, but to generate lift. The long edge fwd generates more lift.

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It does get confusing.

When the board is a foil shape like the composite board you want the hydrofoil to work for you... straighter, thicker leading edge. When it's equally rounded on either edge, I've heard rumor the curve at the tip was to facilitate an upward push in the event of striking a submerged obstacle. I'll go with BB on the longer edge forward to present the greater surface area.

Should you have the "Shadow" style board (stylized and tapered) it's anyone's guess. Some people claim they worked best straighter edge forward, other's say just the opposite. Racing results say that design didn't work well either way and it was quickly replaced by the "Barrington" profile.

a proper foil shape is more efficient and is used on virtually all keels and rudders. You could do little harm by giving that portion of your daggerboard below the bottom of the hull a foil shape, do the rudder also. A keel such as you have isn't providing significant lift, it is only reducing leeway.

As far as I know, factory boards had beveled edges and the diagram in the class rules copies that. Not very efficient, I think it was just a "Get it out the door quick" factory thing. I've dogged mine in a bench and used a Block Plane a couple times to try and get an airfoil shape that eliminates the "hummm" vibration. Still got some vibtration, could be between the keel edge of the centerboard box and the board. As Zeppo says, you could hardly go wrong giving it a better shape.

Webfoot said:

As far as I know, factory boards had beveled edges and the diagram in the class rules copies that.

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Some years were beveled some rounded. The Windward Leg has had several articles on various shaping stratagies over the past few decades. There's a section in The Sunfish Bible on daggerboard shaping. There are also tips in the book for quieting a chattering or humming board. Do some searching here and you'll also find past discussions on the subject.

Are there any unofficial races for Classic Sunfish? Not interested in going with racing hardware since I'm saving my pennies for a Rhodes Bantam, (one of those missed buying oppertunities that I need to put to rest).

I've got the wooden board. If I put the straight edge forward, I get a vibration with speed.

I don't race or anything, I'm just out having fun. If I were to race, I'd put down money for one of the new boards.

Webfoot said:

Are there any unofficial races for Classic Sunfish? Not interested in going with racing hardware since I'm saving my pennies for a Rhodes Bantam, (one of those missed buying oppertunities that I need to put to rest).

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You would be welcomed at all (official and non-official) Sunfish regattas, I am sure. You can find a schedule for the official regattas at the class site:
http://www.sunfishclass.org/archives/2009/2009-sunfish-regatta-schedule.pdf

And, BTW, there is no such thing as a 'Classic' Sunfish as far as racing is concerned (see below for an explanation). But you will have an excellent excuse for not finishing first when you race with the 'hotshots' in their up-to-date boats .

PS: The reason for not having a 'Classic' Sunfish group is that there is no definition for such a boat. Many people sail hybrids. For instance, an old hull with the new (plastic fantastic) daggerboard and a non-race sail. Or some other configuration of the crucial pieces.

minifish said:

I've got the wooden board. If I put the straight edge forward, I get a vibration with speed.

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Yes, that sort of thing can happen when the board is not perfectly faired.

Webfoot said:

Are there any unofficial races for Classic Sunfish? Not interested in going with racing hardware ...

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Thousands..., every season. They're referred to as Open Regattas or Fun Races, something like that. What ever did happen to Will White's (of Sunfish Bible fame) Connecticut River Race. Here's one of the country's biggest... every Tues evening all summer, though some may have to make a bit of a drive. But it's a great example of what's out there, none the less. Gets my vote for best Race Rules.
http://www.duckdodge.org/index.php

Might be something similar in your area. It's not just World Cup racing that makes sailing fun.

Wavedancer said:

Many people sail hybrids. For instance, an old hull with the new (plastic fantastic) daggerboard and a non-race sail. Or some other configuration of the crucial pieces.

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Hey ... that's my boat

...and 95% of all Sunfish