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Polar Diagrams

25K views 20 replies 18 participants last post by  pdqaltair 
#1 ·
Does anyone know of a good resource of polar diagrams for older boats? I am trying to find one for my Pearson 32, without shelling out $300 to USSA.

Thanks!
 
#2 ·
Polar for Pearson 33 below. Can't remember the source but I got about 80 of them...

TWA 6 8 10 12 14 16 20
52 4.6 5.5 6.0 6.2 6.4 6.5 6.6
60 4.9 5.8 6.3 6.5 6.6 6.7 6.8
75 5.2 6.0 6.5 6.8 7.0 7.1 7.2
90 5.4 6.2 6.7 6.9 7.1 7.3 7.5
110 5.2 6.1 6.7 7.0 7.3 7.5 7.7
120 5.0 5.9 6.5 7.0 7.3 7.6 8.0
135 4.4 5.4 6.2 6.7 7.1 7.4 8.0
150 3.7 4.7 5.5 6.2 6.6 7.0 7.7
 
#4 ·
Diagrams are from 33ft (Pearson, Contessa) up to 60ft (Centurion, Deerfoot, Swan). Sorry :(

Catalina I got only 36 model:

TWA 6 8 10 12 14 16 20
52 4.9 5.8 6.3 6.6 6.8 6.9 7.0
60 5.3 6.2 6.7 6.9 7.1 7.2 7.3
75 5.6 6.5 6.9 7.3 7.5 7.6 7.7
90 5.7 6.7 7.1 7.4 7.6 7.8 8.1
110 5.6 6.6 7.1 7.5 7.8 8.1 8.4
120 5.3 6.4 7.0 7.4 7.8 8.1 8.6
135 4.7 5.8 6.6 7.1 7.5 7.9 8.5
150 3.9 4.9 5.8 6.6 7.0 7.5 8.2
 
#14 ·
Thanks but these seem hoplessly optimistic for my TR, WK C36 with newish <4 y.o. dacron sails. I can only comment on the upwind to beam reach figures, since I believe these polars assume a spinniker once past a beam reach and my boat is not set up with spin gear.

Also, Since the wind angle is given as true, I'm assuming the wind speeds are also supposed to be true. Any idea if that's a valid assumption?
 
#8 ·
Polar diagram Beneteau First 45f5

I'm desperately looking for the polar diagram of the Beneteau First 45f5. Unfotunately I'm not able to build up the polar diagram myself, since the boat is located in Hong Kong and I'm living in the Netherlands. In april, we are going to sail the Rolex South China Sea regatta and therefore I would like to have the polar diagram to use it with Raymarine RNS..

Thanks in advance,
Jurgen
 
#11 ·
Re: Polar Diagrams-Newport41-Benetaeu 421

Newport41

TWA 6 8 10 12 14 16 20
52 5.0 5.9 6.4 6.6 6.7 6.8 6.9
60 5.3 6.3 6.7 6.9 7.0 7.1 7.2
75 5.7 6.5 6.9 7.2 7.4 7.5 7.6
90 5.9 6.7 7.1 7.3 7.4 7.6 7.9
110 5.8 6.7 7.1 7.5 7.7 7.9 8.2
120 5.5 6.5 7.0 7.4 7.7 8.0 8.5
135 4.8 6.0 6.7 7.1 7.5 7.9 8.5
150 4.0 5.1 6.0 6.6 7.1 7.4 8.1

Benetaeu 421

TWA 6 8 10 12 14 16 20
52 5.5 6.4 6.9 7.1 7.3 7.4 7.4
60 5.9 6.8 7.2 7.4 7.5 7.6 7.7
75 6.2 7.1 7.5 7.7 7.9 8.0 8.2
90 6.3 7.2 7.6 7.8 8.1 8.3 8.5
110 6.2 7.1 7.7 8.0 8.3 8.5 8.8
120 5.8 6.9 7.5 8.0 8.3 8.6 9.1
135 5.0 6.3 7.1 7.6 8.1 8.5 9.1
150 4.2 5.3 6.3 7.0 7.5 8.0 8.7
 
#13 ·
Most interesting.

Polar Diagrams used to be published with every sailboat review in the old issues of Yachting, Rudder and the like. You do not see them anymore. I wonder why. Perhaps the fact that they START at 52 degrees from the true wind angle is a clue.

As a point of reference, my IOD, designed in 1938, and horribly slow, inefficient, and otherwise unsuitable by modern standards, sailed at an average of 39 degrees to the true wind as measured by the course over the ground between known landmarks on the shore of a relatively narrow channel (The Alameda Estuary, Oakland California.) This was before gps, so some experimental error is in there but this is an average of about a dozen runs up the same channel, roughly six legs, dead to windward usually, and it is taken from courses plotted on a chart, by reference to shore marks at each tack. And we were not pinching or trying to prove point. I only did the measurements after the fact when a question like this came up. We were just sailing.

I suppose if I were the NA of a thing that couldn't go much closer to the wind than 50, or even 45 degrees, I would not want the curves published either.
 
#17 ·
US Sailing has polars for just about anything with sails that floats, but they're not free or cheap. I believe their diagrams show angles of attack from closer to 0 degrees to 180. You can also create your own diagrams empirically, but it's a lot of work to document all the wind speeds, angles, and boat speeds.
 
#21 ·
Most SPs are created by prediction programs, not actual sailing, so more of a guideline than something based on facts. For example, your boat was very likely not built to the specs they are working with (most are over design weight before you move in).
 
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