I'll bet those two know right down to the minute!

NOPE ...

... to the SECOND !!!!!

( ... and that's why you and me are in the middle of the fleet .... and they are at the front !!!)


Harry

Tacking and gybing angles are important on any boat that you race on. How else are you going to call your layline to the top or bottom marks?

What makes them more difficult for cats vs monos, is that they are more speed dependent. Most mono's have pretty consistent angles because of their speeds relative to wind strength are not as drastic (excluding sport boats).

Most cats have dramatically different tacking and gybing angles based on their wind speeds. I've seen anywhere from 80 to 110 degree tacking angles on the same cat. 80 in flat water fully trapped conditions, and 110 in light air or lumpy conditions.

You crew is just asking what the relative tacking angles are so she can get her head out of the boat focus and on "climbing the ladder" up and down the course.

Thanks! Much appreciated.

I would have guessed 45-50 degrees would be ideal upwind, and 125-160 down? But that's a sloop/spin boat with a decent breeze and flat water..

It's all in the telltales...

Racing cats isn't the 'rocket science' that racing slow boats is.

Just go as fast as you can, as long as you can, then tack! (or gybe)

In Rick's excellent book, Catamaran Racing for the 90's, Randy Smyth wrote, "Speed isn't everything, it's the only thing!"

I'd much rather overstand A mark a bit and come in hot, than undershoot it a little and pinch all the way up to it, or worse yet, have to do two more tacks if I come up short.

But on a 24-30 foot monohull, you're only going 5-8 knots upwind (depending on your boat type) and if you've overstood, cracking off 10 degrees isn't going to give you the huge speed increase that it does on a cat. So, yeah, they care about tacking angles and need to get it right, a lot more than we do.

My first goal is to open communications with someone half my age. She asked a question, I'm going to find an answer.

The tacking angle is really just the edge of the bigger picture. I do pretty well just looking over my shoulder to determine when to tack. On the other hand detecting shifts and currents and allowing for each requires a little more finesse (that I don't really have). Maybe she does. But, one step at a time...

Because you won't know where your frickin' boat will be pointing after you tack!!!!!!!!!!!!

Too many hippies in here "Just shut your eyes and let the boat flow maaaaaaan!"

I think we mean the angle between one tack and the next, not the agle between irons and current direction.
Translating your numbers it would be 90-100 for tacking and 40-110 for gybing. (right?)

I think it's not about the telltales. You follow the telltales, true, but first you choose how high you want to go and set the sails for that, I think that's what we are talking about.

For the few measurements with iRegatta I've done, it seems that VMG (towards wind direction) changes little if I open the tacking angle a bit (say up to 10 degrees). Speed increase almost equals the effect of lower angle. And beyond that yo may go faster (though not a lot more) but slower towards wind direction. As said before, it changes with wind speed and conditions. It's cool to measure it, if you don't get crazy about it anyway.. Just set the wind direction and speed and forget about it, let the software capture the data. You can watch your speed every once in a while too and that's it. Then you download the readings and have fun again in front of your computer (in the office maybe..)

Not about the telltales? I won the New England 100 one year, following nothing but the telltales (of course, that was primarily a reaching race, on a year that the wind angle made it tough to fly a spinnaker).

Of course, that's on a Hobie 16, the jib telltales are everything (Doug Baker taught me this). Upwind, I rarely look at the Windex, unless it's blowing over 15 knots; at which point, I can't get the windward jib telltale to fly unless I pinch to the point that we nearly stop. In light to moderate breeze, I just sheet in and steer to the jib telltales. I can actually point higher this way in lighter, flatter water than I ever could just by watching the Windex.

Mike

You just sheet in and steer to the jib tell tales. Right. But first you decide how much you sheet in an how you setup your jib blocks if adjustable. That's where you decide how high you will point, telltales come later.

You can also see see your tracks to figure out your tacking angle:

I've been using a Garmin Foretrex, but it is such a pita to upload!

For that and other reasons I've ordered a Speed puck.

One can also check polars (although there do not appear to be many good sources) to get a rough idea of usable tacking angle and the tradeoff of pinching and VMG, etc. A few links/articles include:

http://www.hobiecat.com/forums/viewtopic.php?f=9&t=10337&start=0

Page 7 of the PDF here: http://www.hobieclass.com/site/hobie/ihca/downloads/hobieu/HobieU.pdf

and here (a theoretical comparison): http://www.thebeachcats.com/OnTheWire/westnet/_lpm/hobie/archives/v1-i3/feature3.htm

From the hobie pdf page 7 above, the best tacking and gybing angles for that polar would be 100° and 100°. (points at 50° and 130° on the plot).

None of them show tacking angles less than 90degrees so I'm a little skeptical of those claims to contrary.

Anyone have an explanation?

the faster you go, the sharper the angle of your apparent wind becomes. You can point higher, but you go slower.

Yes, but I'm not seeing where that will yield tacking angles of 70 or 80 degrees unless it's a measure of apparent wind.

The tacking angles cited above are for true wind not apparent.

Those polars show straight-line speed, not VMG. Depending on the conditions, it may very well be better to sail higher/deeper to get around the course faster.

On a Hobie 16, I have seen that when the wind shuts down, and the race isn't abandoned, the best course downwind is as straight to the mark as you can go without gybing.

Mike

And they're also only for 10 knots (I think it was 10) of boat speed. As the wind speed changes, the polars change for each boat.