Point of Sail
- Thread starter charliegrau
- Start date
As long as I'm learning something new w/nearly each post, I'm willing to continue. The issue with the polars was raised by Jackdaw sometime ago, and then again today by CraigS. So, now it's been addressed. But, we may be getting near the end!!
KG, I personally, believe that POLARS are completely overrated.As long as I'm learning something new w/nearly each post, I'm willing to continue. The issue with the polars was raised by Jackdaw sometime ago, and then again today. So, now it's been addressed. But, we may be getting near the end!!
The reason I feel this way is that they are "Obvious."
For most boats, the fastest POS is a BEAM REACH.
Gee, who woulda thunk?!?
Staked. Time to find an anchor thread. They never end.
I just noticed you unstaked it, Stu before I could put this post in
I just noticed you unstaked it, Stu before I could put this post in
Well, it's been more interesting than trying to explain to a guy who's never owned a boat before the age of 50 why he shouldn't try to sail around the world with his new wife in a 15-yr old MacGregor 26.:cry:
PS [Forgive me!]
PS [Forgive me!
]
Wow, she's GOTTA be a wonderful person to even think about going on that trip.:dance::dance::dance:Well, it's been more interesting than trying to explain to a guy who's never owned a boat before the age of 50 why he shouldn't try to sail around the world in a MacGregor 26 w/ his new wife.:cry:
PS [Forgive me!
Regardless of the boat...
They'd have to figure out the apparent / true thing first...is she an apparent wife or true wife...might make a difference.
Good point.
That must mean "second" or "first" wife.
Kinda like sailing...
My first wife was really apparent...
The second (and current) is TRUE.
All talk of wives aside...
I spent a little time tonight trying to understand polar sailing diagrams, something I wasn't familiar with. They're interesting in that they quantify how far you have to really sail off to make it fastest to a mark directly down wind when the wind is light, and how that angle changes as the wind speeds up, but maybe that's a topic for another thread. Anyhow, thanks for the lesson.
I spent a little time tonight trying to understand polar sailing diagrams, something I wasn't familiar with. They're interesting in that they quantify how far you have to really sail off to make it fastest to a mark directly down wind when the wind is light, and how that angle changes as the wind speeds up, but maybe that's a topic for another thread. Anyhow, thanks for the lesson.
As I said above; as long as something is being learned; it's worth the "back-and-forth!" But maybe a new thread is warranted.
Maybe the thread is ready to die, but I can't let this one go.KG, I personally, believe that POLARS are completely overrated.
The reason I feel this way is that they are "Obvious."
For most boats, the fastest POS is a BEAM REACH.
Gee, who woulda thunk?!?
For sure they have limited interest to the average sailor; as most boats without a spinnaker are fastest on a beam reach. The speed is probably close to hull speed.
But polars are key inputs to high-level racing teams; used to monitor windward and leeward performace. They are always viewed in terms of true wind.
For downwind performace, you must sail your boat at an angle that optimizes boat speed to progress to the mark. This is never dead diwn wind (DDW). As you can see in the example below, the angle can vary widely (from 140 to 170 true) based on true wind speed and cannot be ignored if your want to race well. The 'ticks' mark the optimal speed/angle point.
Upwind, the best way to do this is not monitor wind angle, but target boat speed. This is becase the actual upwind angles only vary a few degrees. At a particular wind speed, if you are slower than your target you are likely pinching, if you are too fast you are likely footing.
While the graphs are fun to look at, the tables are much more handy on the boats we have several of these posted on the First 260 for the whole crew to see.
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Does picking the best TWA going downwind make use of a VMG calculator; your GPS, perhaps?
Also, the diagram may appear a bit hairy, but I actually find it refreshingly simple. There are no "categorical" points of sail to try to fit into a continuum of relative headings, no silly illustrations showing sailboats with "impossible" sail trim, and thus no need to fret over what "wind" is being referenced; no definitions to deliberate. Using a polar seems analogous with playing a piano by sight-reading of the music rather than from memorization of it! I can see why your racing buddies would think it strange that anyone would question the reference wind if working with these diagrams much.
Yes, best upwind or downwind speed is a pure VMG calculation. On the downwind curve in particular, you can see that point is at the optimal angle of boat speed and downwind progress.
While racing downwind, you drive and trim to match your polar TWA to the true wind speed. Gibe to stay on the knocked board.
Yes, polars and sail choice chart on TRUE are important because there is no need to convert to the apparent that occurs AFTER YOU MAKE THE CHANGE. True is always true. Apparent changes after you turn,nor your boat speeds up of slows down.
Polars
Jack's right, they are important, I was somewhat too glib in my first dismissive post. They are much more important to the racier skippers among us. The reason that I feel that way, however, is that I have found them remarkably similar, even between boats, but again, if you're using them to compare boats for racing, of course one would see the difference, which, perhaps, could be made up in the real world by PHRF anyway.
What "the average Joe" who may not have spinnaker gear can learn from polars is the beam reach is fastest, DDW is slowest. Having a polar for your boat can be quite helpful for many different reasons.
Jack's right, they are important, I was somewhat too glib in my first dismissive post. They are much more important to the racier skippers among us. The reason that I feel that way, however, is that I have found them remarkably similar, even between boats, but again, if you're using them to compare boats for racing, of course one would see the difference, which, perhaps, could be made up in the real world by PHRF anyway.
What "the average Joe" who may not have spinnaker gear can learn from polars is the beam reach is fastest, DDW is slowest. Having a polar for your boat can be quite helpful for many different reasons.
I was looking at polars when I was boat shopping. I was not shopping for racing just trying to avoid getting a dog. I eventually just started looking at handicap ratings. That kind of helps, but I discovered some boats are only fast down wind with a kite.