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Old 13-02-2018, 08:33   #1
rom
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Upwind performance of condomarans

Hi there ! Cotemar yesterday posted a polar for the Lipari 41 which got me thinking ... It shows ~6.2 kts boat speed @ 40°TWA, which translates into 31°AWA (!) and 4.75 kts VMG to the wind.

Ok, I was impressed (not to say having a hard time believing it) as my best with my L440 is about 60°TWA.

So this morning I decided to try harder at close haul, see screen capture attached. I measured each angle and it shows that I am averaging 58°TWA, 7.2 kts seems like a correct average speed.

And so this makes a VMG of 7.2 kts * cos(58) = 3.82 kts.. (on the ground !)

Some thoughts:
- my boat is in cruising mode (not light weight)
- I am using the AP in wind mode. Could achieve 38°AWA in these conditions. Below that it would do some mistakes and kill the performance.
- the state of the sea was not perfect but still rather good, 50cm swell/chop.
- I had 16 to 20 kts AWS and 1 reef in the main. Ok that one makes a big difference with the polar conditions @ 20 kts TWS.
- I am showing measures "on the ground", meaning they including drifting.
- I believe my mainsail doesn't have a good shape for close haul
- trimming ? oh yes, F. Gabart may have done a bit better, but not much room for improvement here.
- the time enroute & avg speed from the screenshot are not correct unfortunately as I started&stopped opencpn/track before & after departure & arrival.
- Those are my preferred sailing conditions, easy on the boat, flat seas, good avg speed !
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I would be interested to see what you condo tracks look like ! cheers
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Old 13-02-2018, 12:03   #2
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Re: Upwind performance of condomarans

we have lots of current and eddies here so virtually any pic of track is affected by currents.

However, based on AP tack setting by the first owner that sailed from france to AU, over the ground angle is 110 deg which i believe is approapriate average.

In flat water especially now with new square top and stronger winds i can go below 90 deg but flat water. In flat water AP can do 30 deg app but have to increase sensitivity to 5.

Realistic ocean conditions actually produce 110 or so. It appears 38 app is overall best angle to go windward in most conditions. If smoother water this goes to 34, if rougher more like 43, and if really rough or strong winds to 50. My boat loaded around 2.5 T above light .

However, if you in a hurry, active driving, continuously finding optimal angle, can increase VMG a bit on average.

Also increasing app angle for 3 deg, often increases speed which decreases drift angle and increases VMG, so in general if in doubt increase angle.

thats how much i have learned so far.
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Old 13-02-2018, 12:11   #3
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Re: Upwind performance of condomarans

Did a fun race on a friend's lagoon 380. On the windward leg we sailed at about 33-35 apparent, doing around 8 knots in about 20 kts true.
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Old 13-02-2018, 12:23   #4
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Re: Upwind performance of condomarans

It is hard to use polars unless you know the sea state too, as sea state makes a huge difference.

With the polars being in 20 true and the boat unreeded the helmsman will/can be sailing in "high" mode, where they can be luffing both the jib and main quite significantly. You see this a lot on monos in a seabreeze. (We always tend to reef less when it is sunny).

So if I wanted to make the polars as nice as possible I would lighten ship, clean the bum, check the prop has folded, get rid of the dinghy on davits and sail on very flat water in about 20 true. Then sail by boatspeed and pull her up in the gusts, keeping her moving well and not steering by wind angle or sails. It is called by some racers - 4th gear - depowering mode, but it is can be quite fast in flat water.

Even Etchells, that point incredibly high, have to go low mode in chop and slop. It all depends on how powered up they are and the state of the sea. 20 knots and flat water would be ideal for getting the best polars you can. But it is not useful for different conditions.
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Old 13-02-2018, 12:47   #5
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Re: Upwind performance of condomarans

Quote:
Originally Posted by arsenelupiga View Post
In flat water especially now with new square top and stronger winds i can go below 90 deg but flat water. In flat water AP can do 30 deg app but have to increase sensitivity to 5.
Ha ! I like to hear that a good AP can help there, thanks ! It's on my "next 2 years" purchase list .. with so many other expensive things

But ... I don't believe you tacking 90° on the ground, you have to show me a track !
Unless maybe, is it you whose L400 is faster than an outremer ?
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Old 13-02-2018, 12:50   #6
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Re: Upwind performance of condomarans

My Lagoon was fairly deep draft for a cat. Still, it's not an upwind machine. It IS an upwind machine with the lee motor idling, gaining maybe 15 degrees! and using maybe 1+ pint an hour of diesel!
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Old 13-02-2018, 12:53   #7
rom
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Re: Upwind performance of condomarans

Quote:
Originally Posted by 44'cruisingcat View Post
Did a fun race on a friend's lagoon 380. On the windward leg we sailed at about 33-35 apparent, doing around 8 knots in about 20 kts true.
I was worried you were about to tell us about the perf of your own racer ! ok, that is very good, and though not as good pointing as the Lipari's polar, it may be as good a VMG, but we you don't say about TWA. L380 is quite a bit shorter so I suspect you had good sea conditions.
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Old 13-02-2018, 13:10   #8
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Re: Upwind performance of condomarans

Quote:
Originally Posted by rom View Post
Hi there ! Cotemar yesterday posted a polar for the Lipari 41 which got me thinking ... It shows ~6.2 kts boat speed @ 40°TWA, which translates into 31°AWA (!) and 4.75 kts VMG to the wind.

Ok, I was impressed (not to say having a hard time believing it) as my best with my L440 is about 60°TWA.
I don't know which polar Cotemar has posted. All of the factory supplied polars (if this one is so) are b...s... They are generated by computers not taking into account sea state and some other factors.
I've sailed Lipari (I actually own one) and raced against L 444. Under similar conditions, L440 is much faster and can point easily 5 degrees more.

The best I've seen was a GB 67 sailing to 22 AWA at 20 kts true making double digit speeds in relatively flat water. Meanwile, I have to say that the kind and state of sales makes a huge difference in upwind sailing.

Cheers

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Old 13-02-2018, 15:01   #9
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Re: Upwind performance of condomarans

Quote:
Originally Posted by Cheechako View Post
My Lagoon was fairly deep draft for a cat. Still, it's not an upwind machine. It IS an upwind machine with the lee motor idling, gaining maybe 15 degrees! and using maybe 1+ pint an hour of diesel!
Sorry I don't understand what you mean by that ... what's the point of having an engine running at idle ??
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Old 13-02-2018, 15:09   #10
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Re: Upwind performance of condomarans

Quote:
Originally Posted by yeloya View Post
Under similar conditions, L440 is much faster and can point easily 5 degrees more.
Hey Yeloya, yes it is also my experience that the L440 is faster than the Lipari, but I was having doubts about the pointing ability.

Lipari polar posted by Cotemar is here:
FP Lipari 41 Polar Diagram
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Old 13-02-2018, 15:40   #11
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Re: Upwind performance of condomarans

Quote:
Originally Posted by rom View Post
Sorry I don't understand what you mean by that ... what's the point of having an engine running at idle ??


Idle in gear
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Old 13-02-2018, 16:02   #12
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Re: Upwind performance of condomarans

Quote:
Originally Posted by yeloya View Post
I don't know which polar Cotemar has posted. All of the factory supplied polars (if this one is so) are b...s... They are generated by computers not taking into account sea state and some other factors.
How do you deal with sea state and polars correctly? It seems to be a multidimensional problem.

Are there correction factors or do you really have to consider
1) true wind angle
2) true wind speed
3) primary swell angle
4) primary swell amplitude
5) primary swell period
6) secondary swell... ?

What about rain, sleet etc. How can polars deal with this?

Maybe a normal polar can be used with correction factors? Does anyone have substantial data or insight?
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Old 13-02-2018, 16:04   #13
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Re: Upwind performance of condomarans

Quote:
Originally Posted by boat_alexandra View Post
How do you deal with sea state and polars correctly? It seems to be a multidimensional problem.



Are there correction factors or do you really have to consider

1) true wind angle

2) true wind speed

3) primary swell angle

4) primary swell amplitude

5) primary swell period

6) secondary swell... ?



What about rain, sleet etc. How can polars deal with this?



Maybe a normal polar can be used with correction factors? Does anyone have substantial data or insight?


To add to this, is there a standard for polars? Like STC conditions?
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Old 14-02-2018, 00:50   #14
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Re: Upwind performance of condomarans

Quote:
Originally Posted by rom View Post
Ha ! I like to hear that a good AP can help there, thanks ! It's on my "next 2 years" purchase list .. with so many other expensive things

But ... I don't believe you tacking 90° on the ground, you have to show me a track !
Unless maybe, is it you whose L400 is faster than an outremer ?
one day in the future, when you start ignoring what CF experts say, you will experience yourself. But if you do not go down to 30, 27 app you will never know.

One can easily with lagoon do <90. You need say steady 20 kn true or more, full sail, and flat water. Instead of reefing, you decrease tacking angle.

On your surprise you will start going faster than monos, and better angle. This will hurt some egos around you. And boat will be happy. And you will see <90, assuming no currents.
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Old 14-02-2018, 02:11   #15
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Re: Upwind performance of condomarans

Quote:
Originally Posted by Sailmonkey View Post
Idle in gear
yeah I suspected.. but I still don't see how this would help when going upwind at 5+ kts boat speed. At best this will make less drag if you have fixed props but I have folding props... Now if you push the revs a little you will just get more weather helm. I can only imagine he was talking very light wind conditions.

Starting at 7 or 8 kts TWS my L440 goes upwind pretty much like in the track I posted and would do so at about 5 kts boat speed.
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