Arrgh, Billy, take in the mainsheet a tad woodja?

 

Probably close reach, but maybe close hauled. It depends on the boat's SOG (if there's no current).

To determine with certainty, you'd do the trigonometry to calculate the true wind direction and speed over land, then use that true wind vector to re-calculate the apparent wind after doing the 180. You can't do this calculation without the boat's SOG.

I wrote out the necessary equations to convert apparent to true wind in a calculator plugin in OpenCPN so I can get true wind direction over land in real time. I use it when doing a lazy daysail to ensure true wind is at 90 so I can have a beam reach in both directions. My wife gets annoyed when I beat too hard going out on a hot steamy day, and than we sweat like crazy because of low apparent wind when running back.

 

I don't think you can sail the same point of sail all things being equal on reciprocal magnetic courses. check your math or educate me.

 

Stalled? ;-) Hmm...It's late, I've been out in the sun and rum, but I'll bite. The Apparent wind is forward of the True wind. If your apparent wind is on the beam then the True wind is Aft of the beam. Turn the boat 180 deg. in light air and you'll lose boat speed and thus apparent so now the True wind is forward of the beam. How much forward..? Close Reach? Maybe Close Hauled. Any increase in boat speed moves the apparent wind forward, so that 180 degree turn may need to be 200, 210..?

 

Without knowing the apparent wind strength is it possible to tell the true wind angle on the reciprocal heading?

If you did know the wind strength at 90 degrees, how would you solve for wind direction on the reciprocal using either trig or vectors?

 

the apparent wind is forward of the true wind... so a 90 deg apparent beam reach on one tack would be close reach on sailing a reciprocal mag course... assumes no current and no waves.

apparent wind speed would increase on the close reach

 

Hey,

Somewhere around 45 degrees.

Barry

 

Need boat speed to do this calculation.

 

Isn't that what rum is for?
Tack the boat and trim the sails to whatever the wind decides it's going to be, and not care very much.

 

Without giving an answer, I just thinking when I saw the topic "Hey, that would make a good name for a boat!"

 

I do point out to students that when we sail close hauled on one tack the Windex feather is over the flag.

When we tack the Windex feather is over the opposite flag.

The two flags are 60 degrees apart even though our tack was 90 degrees.

Sort of a related topic.

This subject came up racing last night.
To be honest I never really thought too deeply about it in relation to a 180 tack.

 

Apparently the passing wind is not well understood by many and we all have to steer our own course.

 

So I am certified 101,103,104 and I have no clue .... :C beam?