rudder skeg fairing strips

[ngmayo]

I've not gone through 2 sets of fiberglass skeg to rudder fairing strips on a Caliber 47 built and installed by 2 different yards. They literally break off in pieces over time. The boat also didn't have any when I bought it. I'm thinking about going with home copper roof flashing and just replacing every repaint and chocking it up as a maintenance cost. something like this: https://www.amazon.com/dp/B07MYM5LB7..._ov_lig_dp_it/

Any reason this is a bad idea?

Thanks

[Bill O]

Isn't the copper going to bend and stay out if you turn the helm over hard? If so, it defeats the purpose and will create more turbulence.
I don't have them (yet), but would think plastic would be better. How about a vinyl flashing instead or something a little heavier?

[fourlyons]

I used Formica (high pressure laminate) on mine, still fine 12 years later.

[ngmayo]

Originally Posted by Bill O

Isn't the copper going to bend and stay out if you turn the helm over hard? If so, it defeats the purpose and will create more turbulence.
I don't have them (yet), but would think plastic would be better. How about a vinyl flashing instead or something a little heavier?

The 4-layer fiberglass keeps breaking so that is a big fear I have with vinyl. Really scratching my head though if maybe vinyl would be better than 4 layers of fiberglass. The width is 4" width with over 1" on the skeg and about half inch of gap. Also rudder base where it comes in contact is rounded so don't know that it will bend. I imagine with the rounded rudder there would be a maximum deflection on a hard turn that may not be much different than at rest. However, a very good point also have a concern about bending into the gap. Glad to hear others have had success with Formica a hard plastic that others have used it good to know about. Wouldn't have to replace all the time. Thanks again fourlyons.

[stormalong]

Do you really need fairing strips? That is something used by racers to get the last 1% of speed. Most boats don't have them.

[MJH]

Originally Posted by ngmayo

I've not gone through 2 sets of fiberglass skeg to rudder fairing strips on a Caliber 47 built and installed by 2 different yards. They literally break off in pieces over time. The boat also didn't have any when I bought it. I'm thinking about going with home copper roof flashing and just replacing every repaint and chocking it up as a maintenance cost. something like this: https://www.amazon.com/dp/B07MYM5LB7..._ov_lig_dp_it/

Any reason this is a bad idea?

Thanks

I've been considering installing skeg fairing strips. All users please include some photos and opinion on how it performed.

~ ~ _/) ~ ~ MJH

[ngmayo]

Attached is what I was given by Caliber and given to two boat yards. Both ripped off. I do wonder if they followed the directions though I'm thinking about the Formica or copper solution. Kind of not wanting to take the previous screws out under water. So was just brainstorming before a fall haul out.

[fourlyons]

Mine have"worked" fine, they cover the gap. What it gains me I can't measure or feel, it just seemed like a good idea.

The one thing I would add though is that after sometime, the Formica curled a little. Both pieces curled in the same direction, away from the finished face. By habit I had installed it finish face out, so it worked out fine.

This is the best picture I have of it right now.

[slug]

The fairing reduce rudder cavitation

When you make new fairings use biaxial 45 -45 fabric

Conventional 90 -0 fabric has 50 percent fewer fibers crossing the joint

In addition fibers crossing the joint at a 90 degree angle fail prematurely

[thunderhoof]

You might consider a small redesign where the attachment to the skeg is moved forward and the overlap with the rudder is reduced. This would reduce the deflection of the fairing strip.
On the hard move the rudder to full deflection to see if there is too much bending force on the strips. Test some strip material by itself to see if can comfortably take the expected deflection.
You might also fair the contact area with the rudder so that the end of the strip does not dig into the rudder at full deflection.


... Advice is worth what you pay for it.

[thunderhoof]

Look at the strip on the opposite side from the rudder defection.
If the rudder is at all balanced then the leading edge opposite the deflection will be trying hard to bend the strip close to the attachment with the skeg, causing a lot of bending stress.

The more I look at it seems to me that the fairing strips should barely touch the rudder as it moves through its full deflection.

[Pete7]

Originally Posted by slug

The fairing reduce rudder cavitation

Is this worth while on the average cruising yacht? I guess we have a gap between leading convex edge of the rudder and the concave rear edge of the skeg which less than the thickness of my fore finger?

I note what looks to be an outboard engine well in the photo by Fourlyons (not OP). I would have thought making a hatch to fill this large hole in first might produce the greatest improvement.

Pete

[CassidyNZ]

Originally Posted by Pete7

Is this worth while on the average cruising yacht? I guess we have a gap between leading convex edge of the rudder and the concave rear edge of the skeg which less than the thickness of my fore finger.

Yes, I was wondering what I was missing. The gap between the rudder and skeg on my boat is small enough to make application of anti-foul between them a challenge and the leading edge of the rudder is rounded. I wonder about the drag/cavitation of this compared to the 3-blade fixed prop just ahead of it.

Actually I saw these tabs for the first time the other day on a Beneteau when in the boatyard doing my maintenance. I thought they must be quite rare - apparently not. I thought then that unless the leading edge of the tab was rebated into the skeg to be flush, the turbulence would be better without it. The fact that the OP has had two sets “ripped” off implies that the turbulence on the leading edge of the tab is substantial.

[fourlyons]

Originally Posted by Pete7

Is this worth while on the average cruising yacht? I guess we have a gap between leading convex edge of the rudder and the concave rear edge of the skeg which less than the thickness of my fore finger?

I note what looks to be an outboard engine well in the photo by Fourlyons (not OP). I would have thought making a hatch to fill this large hole in first might produce the greatest improvement.

Pete

Hi Pete,

Yes you're right of course that the outboard cut-out produces drag (and I have two!) but it has proven too difficult for me to come up with a simple, convenient, easy to use solution. When I launched the boat I did have doors but soon took them off; it's still on my list to do list though. Having said that, I think drag is cumulative, and the fairing strips were easy.