True vs Magnetic course to a mark

tmod123

New member
35
0
Does anyone know if Race Committees
In the US standardize on True or Magnetic GPS headings when setting marks?
 

nolatom

Super Anarchist
3,626
652
New Orleans
Come sail and race in carefree New Orleans! Many things won't matter down here, including True versus Magnetic:


Unlike Massachusetts where I grew up, and yes it was always Magnetic for mark-setting. True was for rich people who had electronics.
 
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TJSoCal

Super Anarchist
It's a lot easier to set a GPS device to display magnetic than it is to do the variation math to convert from a hand bearing or binnacle compass to get true bearings.
 

JohnMB

Super Anarchist
2,839
609
Evanston
It's a lot easier to set a GPS device to display magnetic than it is to do the variation math to convert from a hand bearing or binnacle compass to get true bearings.
Only for the racers to have to convert it right back to magnetic to make it useful.....
 

Brass

Super Anarchist
2,759
171
Does anyone know if Race Committees
In the US standardize on True or Magnetic GPS headings when setting marks?

World Sailing Race Management Manual

H5
All Race committee vessels used for major events (signal, pin, finish and mark vessels)
should be equipped with a GPS. All GPS units should be set up to display as follows:
• Distance in Nautical Miles (nm)
• Time to local time zone in 24 hour format
• Compass bearing in magnetic
• Latitude and Longitude in decimal minutes (example: 39 27.928 North, 034
17.464 East)
• Map Datum WGS 84


RRS Appendix LG

9.2 No later than the warning signal, the race committee signal vessel will display the approximate compass bearing of the first leg.
 

lrak

New member
1
0
It easy to switch back and forth between true and magnetic bearing. Most sailing applications should be able to do it for you.
 

pqbon

Member
289
65
Cambridge UK
Addition and subtraction are hard?
When you are working hard and focusing on racing -- don't add anything to the process you can simplify. Expecting the helm and tactician to do conversion between magnetic and true and running your instruments in true with the binnacle and hand-baring compasses being magnetic in nature is way more complexity than you want on the course.
All it takes is one mistake on the conversion -- and you've shot yourself in the foot simply for "more accuracy".
 

dacapo

Super Anarchist
13,640
1,572
NY
Quite honestly in a 1/2 -1 mile beat magnetic variation, and for that matter , the exact compass heading of the windward mark means dick to me. 3,5,7 degrees can be attributed to many variables including wind direction wind strength the roll of your boat the roll of the RC boat most importantly operator error. I could see the mark and point my bow to the mark prior to the start, and get a favored side of the starting line…. that’s all I need
 

Sidecar

…………………………
3,132
1,498
Tasmania
when variation is west magnetic is best
when variation is east magnetic is least
Error west compass best. Error east compass least.

FWIW, MV down here is 15E, so it does matter. On the other hand, I have raced in places where MV is 0, Copenhagen, Denmark, IIRC.
 




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