Polar diagrams anywhere?

[djtopper]

They seem quite hard to find. I know a given boat's performance will vary depending on load out, but still. You would think the diagrams would be part of any detailed spec. EG., you might be able to see quite clearly how a newer model outperforms an older one, etc...

I'm aware of Multihull Dynamics, Inc. - Home which is an excellent site. But no polars.

[colemj]

Many of the French boats have polars as part of their marketing material. They are VPP generated, and not actual sailing experience. They are very generous - I know of none that have actually met those polars.

They would be meaningless in deciding between makes/models. Most boats come with poor sails and do not meet design weights right out of the box. Even accurate polars would not tell anything about how any one boat will handle cruising gear or planned sailing conditions.

On the other hand, they are very easy to generate once you have bought a boat! There are even software programs that automatically collect the data while you are sailing and give you a nice averaged graphical data set.

Mark

[djtopper]

They would in theory provide some info similar to what other measures like Bruce Number, SA / D and so on do, no?

[thinwater]

They won't tell you anything about pitching or tacking agility, but they will (if based upon sailing) tell far more.

I generated some for my boat. After some tweaking I find I can mostly hit hit the numbers for the next larger boat in the group (32 vs 36).

Sail Delmarva: Speed Polars

[colemj]

If you trusted them, then I guess they would have some usefulness in comparing boats. I have yet to see a production boat come anywhere near their marketing VPP polars.

Mark