Beneteau 40.7 Rudder

[Green Flash]

I am new to this group so please forgive if I do something
wrong.
I have Beneteau 40.7 Hull 676, Green Flash here in Hawaii and
another boat Cazan is also here. She was the last of the 40.7's
manufactured, hull 737.
We have have both had some rudder issues that may play to this
situation. Cazan's rudder was replaced by beneteau and its owner
obtained the original specs for the rudder from the Farr office. Both
their original rudder and the replacement did not have carbon fiber
stocks, but "composite" stocks. I took mine out, and mine was also
"composite" not carbon fiber.
Both Cazan and us experienced a high level of sensitivity of the
boats to rounding up, so after getting the farr specs, they made
templates which showed that the rudders as originally provided were in
places close to two inches shorter fore and aft than the farr
requirements. They told me, but I did not see it, that Farr did
specify carbon fiber in the posts. Beneteau has denied to us that
these boats were ever supposed to have carbon fiber rudders.
The composite rudder posts appeared to be solid and in tact so
we did nothing with them. However, we did increase the area of the
rudders to match the original Farr templates.
They tore their rudder open and found that the rudder did not
contain a lower paddle providing stiffening to the back edge of the
rudder which was part of the original spec, so they installed that.
Also, the rudders were a little bit fatter side to side than the farr
spec. In my case, there was enough gel coat to remove that it could be
brought back to the templates without grinding any glass.
My rudder was in much better shape than theirs. No internal
leaking. I decided to have the layup to expand the area to match the
Farr spec done with Cabon Fiber and also to have the entire rudder
encased in two layers of cabon fiber to give it more stiffness and
strength, instead of having it torn apart to build in the missing
lower paddle.
In the case of both boats, the added rudder area completely
changed the personality of the boat from one in which the helmsman was
always on edge about the potential for the rudder to cavitate and the
boat to round up, to one where the rudder never cavitates and the boat
stays under control in all but the most extreme circumstances. The
change made it possible to take advantage of the power available to
the boat in a way that had never been possible.
After Pacific Cup this year (we were not in it) I was speaking
with a sailor from SF who reported to me that some 40.7's in SF Bay
had made the same change with the same results as us.
A year or two ago, a 40.7 from seattle lost their rudder in
the Victoria to Maui race, apparently with the rudder post breaking
off at the hull. There was some question about whether a pre race
backing incident had contributed to that situation.
These are my conclusions: Without the lower paddle, and
without being built of carbon, the rudders may bend and then break in
challenging conditions.
Here in Hawaii our normal conditions are eight foot seas and
20-30 knots of wind. So for us it is necessary to have equipment that
will handle these conditions regularly. My rudder as fixed is ok for
races close to shore in fleets where others are close by. But with
the added area which was needed to give us control of the boat, will
the glass and resin rudder post be strong enough to handle the
increase loading? I don't know.
I am now thinking of having a rudder built from scratch to the
original Farr spec with carbon fiber. I will not take the boat for an
extended ocean cruise or race without doing that. I think I will also
have some additional layup done around the base of the lower rudder
tube where it meets the hull.

[Max Lynn]

Hi Howard:
You cannot do wrong here unless you try to tell us which prop is best for
our boat. Just kidding - it's an inside joke. Your rudder research was very
interesting and your post is imformative.

I'm one of the few 40.7 owners that post here, although I suspect that there
are others who lurk occasionally. I have Hull # 397, and I had the
impression from just looking at my rudder stock that it is carbon fiber.
But I could be mistaken. I am familiar however with the fact that there is
a great deal of confusion regarding this issue, and I think there may even
be some confusion within Beneteau on the issue. I guess you are familiar
with what was posted on the East Coast 407 group's Yahoo site on this
subject, since I see you have posted there.

I can only tell you that I have done a significant amount of heavy air
sailing with this boat and am not afraid to take it anywhere with regard to
rudder strength. I graduated to this boat from an old IOR design with
pinched stern, which was very difficult to sail in heavy air off the wind.
My 40.7 is like a dream, control-wise, when compared to that boat. That's
not to say that some people don't criticize its controllability, and I'm not
familiar with a lot of other boats under those conditions (say 25 to 35kts
TWS with a kite up), so I don't feel qualified to judge their criticism.
From what you have discovered, it may be that I have a larger rudder than
yours was originally.

Several 40.7's in the past have sailed in the local race called the Coastal
Cup (often heavy air downwind) and also complained of controllability
issues, BUT none have lost their rudder. One broke his steering cable, but
that's the ultimate control problem, and IMHO, was likely due to poor
maintenance.

Max Lynn

--
From: benetea...@googlegroups.com
[mailto:benetea...@googlegroups.com] On Behalf Of Green Flash
Sent: Monday, August 02, 2010 11:02 AM
To: Beneteau Owners
Subject: {Beneteau Owners} Beneteau 40.7 Rudder

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23:35:00

[Howard Green]

Max:
Thanks for responding. I sure remember those IOR shapes...we still have
a few around. That old Ranger 37 was a wild ride off the wind.

I came an opposite direction. Before I had a Farr 38. Once we installed
a balanced rudder on it, it was a dream to control, especially off wind.

With the slightly larger rudder area, we found that now the rudder never
cavitates and the boat is controllable almost as good as our Farr 38 was.

In case you want to check yours, I am attaching a little xcel file that
has our rudder dimensions before and after the "fix".

Not sure about Beneteau. Some of the beneteau literature says the boat
has a carbon fiber rudder post and others say composite. Also one of the reviews
talked about carbon. I was under the impression it was carbon when I bought the
boat, but I don't think mine is. When I contacted Beneteau to ask about the
question they had clearly heard a lot about this and were very defensive (though
still polite) and said they had never claimed it was carbon.

From my reading there is about a 2% give factor in carbon fiber and
about 6% in glass. Epoxy has about a 2% factor also. I think it means that
epoxy and carbon work together better, and it explains why we see some glass and
epoxy layups get soft over years. The glass lets it flex and the epoxy breaks
down. I did the carbon encasing thinking that the rudder might be bending and
that might be causing some of the cavitation, and the carbon might reduce the
bending and protect the long term integrity of the rudder.

About the broken cable. We found that the way the cable attaches to the
wheel hub is not very good, so sometimes it slides and when that happens it
chafes. This relates to the bearing question, because our bearings were very
tight...I think partly from swelling, and partly from some possible growth
inside the bearings. We tied a knot at the cable connection point so it can't
slide and that worked to hold it and protect it from wear. But we carry a spare
cable. We cleaned and lightly sanded the bearing surface on the rudder post
with very fine wet and dry and it was still tight but after a few more days of
use the bearings are loosening up nicely.

Howard Green

[Annette]

Hi Howard -

 I know it has been quite a while since this post - but am hoping you might see this. I am doing the Vic-Maui race in my 40.7 next year in 2016 and am thinking about the same type of work. Do you have access to the Bruce Farr specs still? I would love to see them.  Or were those dimensions that you posted the very thing. ( ie the old vs the new rudder dimensions on that spreadsheet of yours)  

With hopeful thanks, Annette

[Green Flash]

Annette:

            Had forgotten my post, and was cruising around on the web and saw yours for the first time.  How was your race Vic to Maui?   It's been now nine years since my post.  We've had our boat in some pretty challenging conditions and the rudder has handled it fine. 

            What I finally concluded is that the 40.7 is sailed by the French on the Mediterranean sea in much lower seas than we are used to so for them lower wetted surface in two-3 foot seas. Also some of the rudders were made for the short keel version, so the rudders were also shorter.  Cazan, that I wrote about before is still here in Hawaii. Haven't seen her much but I hear she is doing fine also with relatively less experienced new owners.

            The Farr Office will sell you a set of the drawings for the 40.7 rudder ... be sure to get the long version. They told me they thought my encasing of the existing rudder in carbon fiber was a really good idea.

            As the 40.7 ages and we see the new designs coming up, I have not yet seen a better boat.  The fact that this boat is a solid glass hull instead of sandwich constructed means to me it will age better and especially handle some of the challenges that can be pretty serious in the ocean...Like running into telephone poles or containers or what have you.  Anyway I'd love to hear your experiences with yours.