Navigating to "xxx.0" TWA
Post by iconPost by Irish Temper | 2020-04-24 | 17:06:49

Hi All,

Sorry if this has already been covered (search function would be great).

I think I've noticed a trend with some of the big name boats and so maybe it's coincidence...

When I use the dashboard and look at another top boat's TWA, a lot of the time I see: 145.0.

On my boat I'm always between .1 and .4 different. ie. 145.3

When I view the polars, the polar indicates for a given set of conditions that 145.0 TWA is the optimum. I see the good guys TWA set to 145.0. I can't get that to happen on my boat and I usually see something like 145.1 - 145.4.

Is there a way to set my boat's TWA to an exact number? Is this a reason why some boats are just sooo fast all the time because they are more often sailing the optimum angle?

Thanks in advance!

David
Irish Temper

commenticon 6 Comments
Post by iconPost by zezo | 2020-04-24 | 17:34:33
That's been already discussed somewhere on the forum.

You can do it with the programmer:

- Set a program 10 minutes ahead WITHOUT TWA lock.
- Lock the TWA
- Check resulting TWA in the dashboard
- If not proper, unlock the TWA and move the programmer a minute or few again.
- Repeat to point 2 until satisfied
- Move the programmer 10 minutes from now. TWA stays locked

Same thing works when programming your next tack. Find the spot where the TWS is integer, lock and slide the time to the correct one.


Post by iconPost by Irish Temper | 2020-04-24 | 18:43:00
Awesome! Thank you I'll give it a try. :)

Thanks for all you do!

David.
Post by iconPost by Austen | 2020-08-31 | 06:28:12
Hi David, were you successful with the TWA fine tuning? i keep trying to follow these instructions, but can't quite get it exactly right...I've managed to move a few decimal points but can't get it to stay on my desires angle...
Austen
Post by iconPost by YourMomSA | 2020-08-31 | 13:47:12
When the wind is shifting rapidly, moving the unlocked course a minute or two can move the TWA by more than 0.1 degree. So sometimes it's impossible to do it at a particular location. So sometimes you need to push the scheduled maneuver a few hours into the future, to a place where the wind isn't shifting as aggressively, do this process to get the TWA angle you want, and then bring it back to the desired time. Really annoying, particularly if you're in a hurry.
Post by iconPost by BooBill | 2020-08-31 | 14:57:06
Also, check the polars to see if it's even worth the effort. There are peaks and valleys in polars in some places, then it's clearly important to be on a peak. Sometimes it's a smooth interpolation, and wouldn't make any matterial difference. Often it's just important to be on the right side of a particular angle. Going past a max VMG number for instance will usually see a rapid fall off in speed, but being a fraction inside the angle might have an identical VMG.
Post by iconPost by Austen | 2020-09-08 | 05:40:46
thank you Mom and Bill for that assistance. Those comments both make good sense.
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