Thoughts on our propeller Oc 411

[Dimitri Liaos]

Our boat is coming soon in the water and we are in thoughts about our propeller.
It is a 3 blade standard, marked SAME RADICE, something like OTE 18 (?) and some
other small things I don't understand. I don't know if anybody else has exact
the same and knows the spec better, size and pitch.
The boat has a theoretical hull speed of 8.4kn which we have casually reached
and surpassed under sail, but never attained under motor, around 7.6 max in flat
water at 2800rpm. We also experience quite some propwalk. The motor is an
(excellent) Yanmar 4JH3 54bhp in pristine service condition and the gearbox
Kanzaki 2.63 reduction.
We are in thoughts. One is to send it to the propshop and have it pitched a bit
higher. Another thought is to buy a 2 blade folder from Flexofold, which had
excellent results in the test, but we are worried for vibration while motoring.
We also own a Catalina 30 which now sports a 2 blade folder, excellent in
forward, reverse and sailing but quite some vibration noises under motor. The
third is to buy an Autoprop.
Our hull is almost identical to the 42cc and 423 as I understand. I would very
much like to hear experiences and thoughts of the group on this
Thank you

Dimitri
AngieL, OC 411 2002
www.telltales.info

[Bill Jarvis]

Dimitri,

If you can only get to 2800 rpm your prop is already over pitched. If you
take it to a prop shop your probably need to have the pitch reduced by at
least an inch in order to be able to get to 3400- 3600 rpm max.

If you really want more performance under sail get a folding or feathering
prop.

All of them are better than a fixed prop.

Bill

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[Carleton Bryant]

Dimitri,

The standard 3-blade prop for the 411 is 18" diameter by 10" or 11" pitch.  Most likely 11" on your boat with the 54 HP Yanmar.  The Yanmar's power is most likely rated at about 3600 RPM.  If you are only achieving 2800 rpm, there is already too much pitch on the propeller and/or your bottom and prop are fouled with marine growth.

We replaced our stock propeller with a 3-blade Flex-o-fold 18" diameter and 12" pitch, which has worked well for us and should work well on your boat.

Best regards,

Carl Bryant

"Gambei"

B411  #53

[Jeffrey]

Prop wars... each prop has it pros and cons. That said I put an AutoProp on
our own OC 400 and a client's Oc 411... both work as expected...seems to be
more power under less rpm's... much better in reverse, less drag and
somewhat faster under sail especially under light wind. Con... is the cost
as this is an expensive option.

Jeffrey Schwartz

-----Original Message-----
From: benetea...@googlegroups.com
[mailto:benetea...@googlegroups.com] On Behalf Of Dimitri Liaos
Sent: Thursday, March 17, 2011 11:35 AM
To: Benetea...@googlegroups.com
Subject: {Beneteau Owners} Thoughts on our propeller Oc 411

--

[@]

Expensive is right, but we have finally passed the break-even point with our Autoprop. With 1600 hours on the Yanmar and savings of 20% on fuel per Practical Sailor, I figure we are making a buck or two. That is being spent rapidly, though. We have run through more dink gas here in KW that anywhere ever. About a mile each way to Garrison Bight, 1.5 miles to KW Bight, generall futzing around and all that jazz is taking over 5 gallons per week. I am so envious of those 15HP 4 strokes, but what the heck. Our Yanmar 8HP Enduro (3d world engine) only cost us $700, so I'll manage. Particularly now that I know how to work on it.

 

Folks who day-sail and don't plan on making a long term floating life will find it tough to justify the expense of an Autoprop, but we really like ours.

Cap in Key West

[Desert_Mariner]

Hello Dimitri,

From Ward Richardson at Beneteau the correct prop for a Yanmar 4JH3E
with Kanzaki transmission is Part # 016925 19X12 RH30. 19 is for 19"
in diameter, and 12 is for 12" pitch. Pitch is distance of travel
through a solid (meaning not allowing for slippage through water) in
one rotation of the prop. My boat currently has an 18x13 Volvo Penta
prop on it and doesn't achieve the expected 3600 rpm that the Yanmar
recommends. I've talked to several Yanmar certified mechanics and
they all say the Yanmar is a "high performance" diesel which needs to
run at higher rpms in order to achieve the best performance and
longest life. They tell me continuous cruising at the lower rpms will
cause carbon ring buildup in the cylinders which will shorten the life
of the engine. My Yanmar maxes out at about 2600 rpm and I have an
additional problem with a high pitched noise called prop sing. I don't
know why this prop was put on the boat, but it's definitely the wrong
prop. I plan to pull it this spring and have it re-pitched.

Dan Berkey
S/V Corvette
B411 LE Hull #269
San Diego, CA

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