DTF

[Spyro]

Just noticed that the dtf is not measured around the waypoints as I am approx 300 miles ahead of MJM an Alistair on dtf but to the next waypoint there is only around 80 miles in it.
I thought on the last leg it was measured around the waypoints.
Now I know I'm not doing well.

 

[Martin_J]

Regarding DTF it is the distance to the next mark that is confusing.

I believe we take the distance to the bisecting angle (that would head out approx ESE from Mauritius) from where we are now... This is the line that you would have to cross to be 'mark rounded'.

The shortest distance from our current postion to that extrapolated line gives distance to first rounding ... the remaining legs are then added to this by way of the shortest distance to each of the remaining marks.

Hope this makes sense. ybw_mjm

 

[Martin_J]

I see now.... from our 'rounding' of Mauritius we have about 1000 miles to PE1 whereas you (in a direct line) will have about 800 miles to PE1.

 

[Spyro]

Hope this makes sense. ybw_mjm

Not really but I realised it also can't be a straight line to the finish as a few mins ago I was the same dtf as PYE-END yet he was 60 odd miles further south.

MJM. If I use the measuring tool you have a straight line to PE1 taking you about 60 miles SE of the next waypoint. This leave you 1840 miles to PE1. I have about 900 to the next waypoint and about 850 from there to PE1. It doesn't make sense to me.

 

[Spyro]

I see now.... from our 'rounding' of Mauritius we have about 1000 miles to PE1 whereas you (in a direct line) will have about 800 miles to PE1.

Yes but I'm almost exactly 300 miles ahead of you in the DTF table and only about 80 miles less than you to PE1

 

[Martin_J]

That was the explanation earlier in the chat..

BUT - I'm beginning to think since I will be well East of Mauritius when I 'round' then it will mathematically measure the shortest line for me to that line then from that line crossing point to the next rounding line - that will not necessarily be at the mark itself.. In my case it will be quite a few miles east of it.. the next mark will be the same for me. Each leg for me therefore seems to be measured with extra distance.