Polars for Predict Wind

[Epicurean]

I'm trying to use PredictWind and realize good polars are critical for the accuracy of its weather routing and departure planning functions. But I haven't sailed this boat enough to develop them. To get going is there an online database of polars that, if I can't find a Mumby, there might be something similar? Or is there someone on CF who has developed a set of Mumby polars? THanks!

[Discovery 15797]

http://www.cruisersforum.com/forums/...es-239347.html

[Epicurean]

Thanks. Unfortunately I don't see any somewhat similar catamarans. I found a 54 foot generic cat with a .pol file. Any idea how to open that? It was zipped and my file reading app gave up.

[wholybee]

The "polars" Predictwind created for my boat by just entering a few values for sailing at 15kt of wind worked much better than polars I found online for my boat.

Point being, I wouldn't bother with Polars you get from someone else. They are either polars for your boat, or they are not. With the polar that predictwind creates, at least it starts with real values for your boat.

[hlev00]

Don't get too hung up on polars. As @wholybee said it is best to just make up your own based on how your own boat sails. I found PW was better with polars but you only need something reasonable. Don't get your hopes too high on the predictions over a long period. So many things change over the course of a passage that you need to keep updating and reviewing anyway.

[Epicurean]

Originally Posted by wholybee

The "polars" Predictwind created for my boat by just entering a few values for sailing at 15kt of wind worked much better than polars I found online for my boat.

Point being, I wouldn't bother with Polars you get from someone else. They are either polars for your boat, or they are not. With the polar that predictwind creates, at least it starts with real values for your boat.

Thanks. Does Predictwind create polars as I go? How does that work? Of course, I'm aware that at the beginning I'm heavily loaded with provisions so I shouldget faster as the passage proceeds.

[Epicurean]

Originally Posted by hlev00

Don't get too hung up on polars. As @wholybee said it is best to just make up your own based on how your own boat sails. I found PW was better with polars but you only need something reasonable. Don't get your hopes too high on the predictions over a long period. So many things change over the course of a passage that you need to keep updating and reviewing anyway.

Thanks. I understand your point and agree. I hope to make some for my boat as I proceed. I was just hoping for a start. Anyway, I did get some from another Mumby owner and, through an iterative process, will try to refine them.