"Polars"by mfgs are ridiculous

[Barra]

Originally Posted by Ex-Calif

As a racer for the last 5 years I find polars useful. To me one must have a baseline.

If a boat is not hitting polars it could be bad sailing or bad rig, excessive loading and in remote cases a bad polar. I found a rig issue in my boat when hitting speed on one tack vs. another.

Without a beseline you dont know where to start looking or even if you should look. If you can explain performance shortfall based on boat load or some other factor than the polar serves its purpose.

There is no other way to set a baseline than with an empty boat. This is the only way one can compare between two boats of the same type as equipment loading will be different.

The other use of a polar is the shape which indicates where you might look for best vmg.

I keep a blank polar plot on board. When I am racing and have time I mark my boat speed and wind speeds. Sort of my own polar. The information is useful to me to see if the boat is changing. Boat load is pretty consistent and the biggest variation is bottom cleanlines (go figure...)

You seem to hate polars and I have said what I think so vive la differance...

My only advice is that when you are getting smoked by a boat of the same type you may want to go back to basics for troubleshooting and basics includes performance plots.

And final couple of questions - Are polars given in true or apparent wind speeds and angles? Did the rep know and did he know the difference? Were you reading true or apparent on the wind guages? I would expect a rep to know, especially if he is selling boats but it would not surprise me in the least that the "marketing & sales" guys are not familiar.

I dont "hate polars" as you say. i just hate unrealistic theoretical polars generated from a design only. Realistic polars are very useful i think we agree on that much whether cruising or racing.

You are reading waay too much into this lah - Im just pointing out how misleading the L39/40 polars are. ie i took them at face value, flew 1200km to test sail the boat and found them to be totally misleading so im just trying to save the next guy that cares about performance the hassel of doing the same.

leopard reps know their polars are idealistic at best but post em here and elsewhere without being called on em. if they tried the same on a racing design there would be hell to pay. as i said find it odd you would defend em without experience on the boat yourself.

cheers
barra