Best way to track wind shifts
- Thread starter danstanford
- Start date
We had a spot on the compass card where we wrote down our optimum tack headings with a pencil. Some race compass come with red tack lines built in. Just sail head to wind BAM right and left tack.
Thanks Everybody. JackDaw, I am interested in more if you have the time.
I do think I need somewhere to write these headings down along with the pluses and minuses so I don't have to think about them.
Keep it coming Folks, I am taking it in.
I do think I need somewhere to write these headings down along with the pluses and minuses so I don't have to think about them.
Keep it coming Folks, I am taking it in.
It is an Axiom but as far as I can tell I don't have the race tools loaded. Their support sucks as far as being able to understand what you have and how to use it unless you are looking for fishing stuff.
I am in Lake Ontario and on the north shore where wind seems to go to die at race time. Are there any guidelines about the length of time between shifts/oscillations? I presume our pre-race work will give us some idea of this but it seems difficult to understand when you are on a little oscillation versus an actual shift versus potentially a persistent shift.
I do understand from my reading that when you get back to your median wind angle from being lifted is the ideal time to tack.
I do understand from my reading that when you get back to your median wind angle from being lifted is the ideal time to tack.
First, here is the PPT to a seminar I do on tactical compasses at WYC.
https://cdn4.sportngin.com/attachme...985.267014463.1564490563-695830981.1548367777
I'll do a separate explanation in next post.
https://cdn4.sportngin.com/attachme...985.267014463.1564490563-695830981.1548367777
I'll do a separate explanation in next post.
Some more thoughts... and some designed to follow up on the concepts mentioned in the PPT.
Why do we track wind shifts when sailing upwind? In short, to minimize the distance/time it takes us to get to the windward mark. See the PPT for lots of detail. But to do this we need two things, summarized below:
1) The ability to reliably sail on the wind. This means good trim, and the constant attention of the helmsperson to notice shifts that will present themselves as as changes to the telltails. The driver needs to honor these changes by turning up or down to keep the boat in trim.
2) The ability monitor the angle that you are sailing on, on both tacks. This means a compass that the driver can CONSTANTLY and easily see from the driver positions(s) on either tack. See more in the PPT, but this is why the best racers will have a compass mounted on the mast. Simple truth: If you cannot see your compass, you will not be good at this.
Keeping track of these numbers is key to learning the median wind for the day. On each side, the tacking angle will swing through a range 5-20 typical of degrees as the wind shifts. Doing this can be a simple mental task, but most write them down as they figure the median. Some devices will do this for you. In all cases it is a judgment call, and a simple datapoint that can drive your upwind strategy.
The PPT will say more, but all else being equal, a boat should tack when the current upwind angle is wider than the median (AKA knocked). This will put you lifted on the other tack, and you are now sailing less distance because your angle to the mark is tighter, giving you much better VMG.
Why do we track wind shifts when sailing upwind? In short, to minimize the distance/time it takes us to get to the windward mark. See the PPT for lots of detail. But to do this we need two things, summarized below:
1) The ability to reliably sail on the wind. This means good trim, and the constant attention of the helmsperson to notice shifts that will present themselves as as changes to the telltails. The driver needs to honor these changes by turning up or down to keep the boat in trim.
2) The ability monitor the angle that you are sailing on, on both tacks. This means a compass that the driver can CONSTANTLY and easily see from the driver positions(s) on either tack. See more in the PPT, but this is why the best racers will have a compass mounted on the mast. Simple truth: If you cannot see your compass, you will not be good at this.
Keeping track of these numbers is key to learning the median wind for the day. On each side, the tacking angle will swing through a range 5-20 typical of degrees as the wind shifts. Doing this can be a simple mental task, but most write them down as they figure the median. Some devices will do this for you. In all cases it is a judgment call, and a simple datapoint that can drive your upwind strategy.
The PPT will say more, but all else being equal, a boat should tack when the current upwind angle is wider than the median (AKA knocked). This will put you lifted on the other tack, and you are now sailing less distance because your angle to the mark is tighter, giving you much better VMG.
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Writing the angles down over time will give you an idea. Its a learning thing.
As for when to tack back, wait until your number goes BELOW the median, meaning you are knocked on the new side. If the wind stays on the number for a long time and you cannot see other boats either lifted or knocked around you, use the balance to sail to the part of the course you want to be in.
Yes, that is one thing I forgot to mention in my earlier post. In your pre-race work recording upwind headings you do want to keep track of the time interval between the shifts. This becomes particularly useful information at the start or as you are approaching a mark. For example, say the shifts are 5 minutes apart and as you are approaching the start, your wind is in a left phase and has been for three minutes, you should reasonably expect the wind to go back right in about 2 minutes. This can impact your starting approach and the tack you want to be on.
It is an Axiom 9 from May of 2018 running the latest updates as of May but I cannot seem to find the race features on it and cannot see how to download them from the Raymarine site. Does anyone know if they should be loaded or if I have to download them separately? I see that in the racing applications I should see dynamic laylines and the ability to input a start line to get a time to burn function in conjunction with the race timer I use all the time.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 23,165
@danstanford this link may help with info. http://themarinenews.com/raymarine-lighthouse-3-9-the-return-of-the-sailing-functions/
Appears you need version 3.9.
Appears you need version 3.9.
Thanks JS! Not sure why this isn't more clear on their web site but I couldn't figure it out at all!
Dan
Dan
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 23,165
Experienced the same problem... It appears that they (raymarine) left the sailing functions out when they introduced Lighthouse 3. That seems like a good reason not to share the omission.
It feels like they wanted to focus on powerboats.
It feels like they wanted to focus on powerboats.
Ray is notorious for making "life altering" changes in the software, and, there does not appear to be any sort of focus group or consultation process. One day features are there and the next version they are gone.
It makes a good case for maybe not upgrading to the latest version of Lighthouse if things are working as expected. I know my mooring neighbour has an Axiom and it has some pretty cool functions that take a pair of i70s to accomplish on our installation with an older a series plotter.
From what I read on the Raymarine Tech Forum, they sailing features were not ready for the initial LH 3 release. They were included in a later update of LH 3, not sure which one but 3.9.46 has them.
RM added more sailing features in LH 3.10 which was released a couple of weeks ago. This recent release does have a few bugs including working with iTC-5.
Like most OS systems, I like to stay a couple of updates behind. Too many companies rather have their users debug their software. Probably cheaper than doing it themselves.
RM added more sailing features in LH 3.10 which was released a couple of weeks ago. This recent release does have a few bugs including working with iTC-5.
Like most OS systems, I like to stay a couple of updates behind. Too many companies rather have their users debug their software. Probably cheaper than doing it themselves.
I would go one step further, based on some of the commentary and suggest that after a thorough review of the docs, go out and spend a day digging into the Axiom functions and see what they do. Out on the race course is not the time to be looking at a display and wondering how to do something or what it means.
Yep but better start in the off season. The LH 3.9 Advanced Manual is 404 pages.
What I did was download the PDF, open it and copy pertinent chapters to MS Word. This way I can skip chapters that I won't be using, make notes, highlight sections etc. Then save it as a new PDF. Kind of a customized manual just for me.
I haven't even started looking at the sailing functions yet.
Yeah but then you fall into our category, once you remember where the boat is - how to use it. Ha ha