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Post by esmerelda on Aug 4, 2020 19:24:19 GMT
Using the site jitter.github.io/orc-data/site/ I have obtained some polar charts for SO40. These would seem to indicate that the boat should do up to 5.3 knots in 6 knots of breeze and up to 6.4 knots in 8 knots of breeze. However our experience is that it is somewhat slower than this and also slower than similar sized boats, which is quite disappointing. Once the wind increases it is better but does not seem to achieve consistent 8 knots plus that the polars would indicate? The boat is shoal draft which I understand will impact leeway, but I wouldn't have thought would make much difference to straight line speed. I realise that the polar is theoretical, but our poor speed against similar sized boats seems to indicate we should be going faster
I was wondering what other SO40 owners think of the performance of their boats and also whether anyone has a Jeanneau supplied polar chart?
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Post by Don Reaves on Aug 4, 2020 19:39:04 GMT
The polar data I've seen has always been very optimistic. Your individual results will vary. What kind of sails do you have, and how old are they? How much gear do you have on the boat, and how is it distributed? Are you very skilled in sail trimming? How clean is the hull? What kind of prop do you have?
There are too many variables involved for you to be able to expect some ideal polar data to fit your boat. I've always used them only as a starting point.
Don
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Post by renegade27 on Aug 4, 2020 20:34:44 GMT
I sail pretty well to the SO35 SD polars, however as you say sail shape, trim, bottom condition, prop, all of that make HUGE differences in speed. THAT, BTW, is the challenge offered by the polars. They show where you have opportunity to increase speed and, for a performance sailor, would set about discovering what could help.
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Post by zaphod on Aug 5, 2020 4:20:01 GMT
Polars assume everything is optimized. Perfect bottom, perfect sails perfectly trimmed.
Your boat should certainly be quicker than what you are experiencing. If you have a fixed prop, then changing to a low drag prop will be the single biggest improvement you will make to sailing performance.
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Post by esmerelda on Aug 5, 2020 11:07:15 GMT
Thanks for the replies
One of the changes we have made is to fit a folding prop which certainly helped
I realise the polars are "perfect world", I was just wondering what sort of consistent speeds other SO40 owners achieved in reality so I'd know how far short we are?
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Post by alex1949 on Aug 5, 2020 17:58:57 GMT
Using the site jitter.github.io/orc-data/site/ I have obtained some polar charts for SO40. These would seem to indicate that the boat should do up to 5.3 knots in 6 knots of breeze and up to 6.4 knots in 8 knots of breeze. However our experience is that it is somewhat slower than this and also slower than similar sized boats, which is quite disappointing. Once the wind increases it is better but does not seem to achieve consistent 8 knots plus that the polars would indicate? The boat is shoal draft which I understand will impact leeway, but I wouldn't have thought would make much difference to straight line speed. I realise that the polar is theoretical, but our poor speed against similar sized boats seems to indicate we should be going faster I was wondering what other SO40 owners think of the performance of their boats and also whether anyone has a Jeanneau supplied polar chart? Hi Esmeralda, just to make you sure those boats can go fast I went sailing today on my SO 40 DS , true wind was 12-14 knots, I deployed my 100 sqm gennaker and at awa of 95 degrees we reached 8.5 knots gps reading. Don't give up the ship.
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Post by alex1949 on Aug 5, 2020 18:52:14 GMT
I was wondering what other SO40 owners think of the performance of their boats and also whether anyone has a Jeanneau supplied polar chart? Hi Esmeralda, just to make you sure those boats can go fast I went sailing today on my SO 40 DS , true wind was 12-14 knots, I deployed my 100 sqm gennaker and at awa of 95 degrees we reached 8.5 knots gps reading. Don't give up the ship.
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Post by esmerelda on Aug 6, 2020 7:13:22 GMT
Hi Alex, thanks for info, that's good to know
How do you find it goes in lighter winds, eg 6-8 knots?
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Post by alex1949 on Aug 6, 2020 22:07:09 GMT
Hi Alex, thanks for info, that's good to know How do you find it goes in lighter winds, eg 6-8 knots? One of the biggest advantage those SO 40' have is it's light displacement. With a good prepared boat (folding prop, decent sails, relatively clean bottom and a good sailing hand),you can expect 60-65% of the apparent wind speed. That is correct especially in light winds. IN heavy winds all boats run fast. For the light winds my favorite sail is the gennaker. Mine is 100 sqm uses a sock to deploy and is very versatile and makes wonders. IN 6-8 knots wind you may expect speeds equal to aws. I fly this sail by itself with no other sail aside. Best experience one can hope for.
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Post by zaphod on Aug 8, 2020 0:58:36 GMT
We had a great sail yesterday on our 39i. (I know it is a different design but it is similar). Conditions were 16 knots TWS, with an A1 spinnaker sailing at 135°AWA, boatspeed in the steady 8.5 knot range with bursts up to 9.5kts.
Our boat also goes pretty well in lighter winds. 7.5 knots boatspeed is very common in 10 knots TWS upwind or reaching.
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Post by zaphod on Aug 8, 2020 22:40:47 GMT
In terms of light wind performance it really depends on wind angle and sea conditions. On our boat sailing upwind in flat water it is not unusual for boatspeed to match wind speed. This pic was earlier today, loaded down with cruising gear and towing a dinghy.
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ChrisD
Junior Member
Posts: 12
Jeanneau Model: SO 40
Home Port: Raby Bay
Country: Australia
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Post by ChrisD on Aug 9, 2020 2:37:48 GMT
sun odyssey performance compared to racing boats polars 1.95 keel
Sail size: the polars are from using a main, that is 15-20 % larger than standard and a 140-150% genoa. With an as new sail , possibly a norths 3di and condition(no more than 12-18 mths old) which will hold the correct sail shape for the conditions .Making use of the maximum hoist and outhaul. Along with the vang, cunningham and outhaul all being use to help.
Rig tune is also very important. I have found with my boat that I also struggle in light winds (up to 8 Knots) to get near these target speeds (carbon 145 genoa and a cruise lam triradial main) and that's with an experience crew who know how to trim effectively. However from 10-12 knots up even at a cruising weight, those polar guides can be reached. The main thing is to go out and enjoy your sailing, if the sail shape doesn't look good its probably not performing at its best for the conditions. A good book that my help is Ivar Dedekam's Illustrated Sail & Rig Tuning
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Post by so40gtb on Oct 4, 2020 1:47:55 GMT
Our SO40 has the deep bulb keel. Replacing the original, 15-year-old Technique Voile sails made a big difference in performance, even with the genoa reduced to 135% from the factory 145%. Optimal trim is important, which is why I fitted the jib fairlead cars for adjustment from the cockpit, early in our ownership. In lighter winds greater than 60 degrees apparent, the North asymmetrical moves the boat quite well. When the true wind is under 4 kt or so, the boat's a slug, especially when fully loaded for cruising. I'd say that our boat approaches its polar chart with the new sails, properly trimmed, and wind above 5 kt, but it would surprise me if the shoal keel would get there, especially close-hauled.
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