Polars (Allen)

In a message dated 3/21/2011 5:05:42 P.M. Eastern Standard Time, al… [at] PaloAltoPhoto.com writes: But I need a break so I am working on how to calculate polars with just a hand held wind meter, your masthead fly, and your knot meter. Anyone else interested in this? I am! Do you need any info from me? Thanks! Paul West '80 Cal 39

Right now I am working through a lot of math and excel spreadsheets doing sensitivity analysis on the method to see if it stands a chance of working. Looks good so far. If anyone has a set of real polars that I can use in the analysis, that would be helpful. The basic idea is that with boat speed, apparent wind speed and apparent wind direction you can calculate VMG. Apparent wind angle can be calibrated with a camera and a little free software. The wind speed and boat speed are a ratio and you can calibrate them against each other. From that and several measurements you can find you max VMG which will give you your target speed and target apparent wind angle. I still need to figure out which target is the least sensitive to changes in the parameters. At this point it is all theoretical but the first application of a non refined version of this got us a win in the third race of a series against a boat that had badly beaten us in the first two races. On Mon, Mar 21, 2011 at 7:12 PM, <pw… [at] aol.com> wrote: > > > > > In a message dated 3/21/2011 5:05:42 P.M. Eastern Standard Time, > al… [at] PaloAltoPhoto.com writes: > > But I need a break so I am working on how to calculate polars with just a > hand held wind meter, your masthead fly, and your knot meter. Anyone else > interested in this? > > > I am! Do you need any info from me? > > Thanks! > > Paul West > '80 Cal 39 > > >

This would also be of value on passages, not just racers I assume, to ensure that max speed is maintained under specific conditions would it not. Not always possible when on autopilot or wind vane and these tools have a course set as the priority, well unless you buy the entire kit from Raymarine which will set you back at least another boat buck (learning that terms faster then I wanted too). but has no effect on wind vane based autopilots. I don't use a wind instrument but would consider a hand held down the road some as that has extended value over a proprietary integrated system. Good stuff Allen. /ch On Tue, Mar 22, 2011 at 2:12 AM, Allen Edwards < al… [at] paloaltophoto.com> wrote: > > > Right now I am working through a lot of math and excel spreadsheets > doing sensitivity analysis on the method to see if it stands a chance of > working. >