Projected position

[rgrenfell]

Hi everyone

Managed to miss the finish line today (which doesnt really help!) on top of running into a lump of land. Both as a result of changing projected positions.

I'm aware that my projected positions line may change after a weather update, but that only happens 4 times a day. Is there a way that my projected line, on a TWA, should change other than that?

R

 

[sarabande]

I sometimes wonder about the WX updates. On occasions they have been late, which affects the projected run line.

This race has been distinctive for radical changes in wind direction and strength, and many top names have been caught out.

I reckon the only way you can track a possible glitch is to log the forecast position, say for nhours ahead prior to a planned WX update, by using the dividers to give a distance and bearing from a static lump of land, and then check for an actual, later on.

It's a fascinating game, and at the moment I resolutely refuse to use the routing software, otherwise it becomes just a follow-my-leader game. Perhaps it explains why I am still ATTOS still to finish, and have been beaten by that noble lady member of the YBW Squadron, Goosewing.


I'd love to have the time to work out a little spreadsheet routine to utilise the polar data, and interpolate it into a VMG to destination, rather than just having VMG to windward from the polars.

BTW are you in any way related to Gunsmoke in the 70s RORC races ?

 

[rgrenfell]

BTW are you in any way related to Gunsmoke in the 70s RORC races ?

I dont think so.
GunSmoke has been the name I've used in online games since my old Bolo (anyone remember that?) days.

R

 

[Martin_J]

Yes - I believe your predictor line will move over a period of time after the weather update is uploaded as the new data is merged slowly into the old.

When the forecast is uploaded, the data is filtered in gradually so as to absorb any bumps or jumps that would happen if a new file was just added in one bang. Imagine your nice TWA sailed course if that jumped in direction each time a new weather update came in.

ybw_mjm

 

[Martin_J]

Sarabande.. Are you asking about Gunsmoke - a Hustler 32 from the 79 Fastnet, that was then renamed Gunslinger and then moved to Falmouth and continued to race in the local racing scene.

 

[Martin_J]

Sarabande....

(Third and final reply tonight - it's late)..

You asked about reading the polars to be able to help with tacking.. and how close you can get to the wind on each tack for best Vmg when you're sailing to a mark that is not directly upwind but involves tacking.. and yes, it's different.

Read the link below by one of the other SOL sailors ..... The only issue is that once you've started all this running through your mind and sailing a different TWA on each tack, you'll be spending much much longer working out a course! In fact working out the last course change will merge into this course change and the next course change and you'll have even less rest.

http://76trombones.wordpress.com/

BTW - Congratulations on just 3.6 miles to go in the New Zealand race...

 

[Dipper]

Read the link below by one of the other SOL sailors

That does me 'ead in!

I won't mind losing to a much superior brain in future.

 

[Greenman]

GunSmoke, the predicted line can move fractionally even during a current weather window. I have been a victim of this,and have watched the predicted line jump off the finish line on the final approach.
Lesson learned,and now do not cut rounding marks and finishing line too fine.