Tacking angle

I've heard 70 degrees for A-Cats.
http://www.harken.com/OneDesign/AClass_Cat.php
Not sure about F16/18s.

It's probably closer to 80-90 degrees for most of us. Tacking angle isn't everything though and is hard to compare to monohull world. Speed is king on cats and although we can sail just as high (or higher) than any other monohull while still going faster, we can get to the top of the course more quickly sitting in the 80 to 90 degree range. Speed through the water increases dramatically as we crack off of the wind.

Talk of tacking angle also ignores the effect of speed - apparent wind angle. Because we move faster, our apparent wind angles are much higher and our sails/mast/tuning are tailored to handle this high apparent wind angle. This is ultimately the limit of getting to the top of the course in short order.

The wind chicken on my old hobie 18 set to 90 seemed to be close.

A rule of thumb for most sailboats is that they tack through 90 degrees. For any given sailboat many different influences affect the actual tacking angle. Some are: water condition - smooth is higher, rough is lower; wind speed - very light is lower, medium is higher, heavy is lower; displacement - heavy is lower, lighter is higher, sail shape - fuller is lower, flatter is higher; boat surfaces - rough is lower smooth is higher; keel or daggerboard length - longer is higher, shorter is lower; cat rigged (main only) is higher, sloop is lower; etc. So using those general guides you can see why the A cat is probably the highest pointing cat design as it incorporates the most influences that give it that advantage. Also you can understand why an F-16 single handed with main only points higher than the same boat with jib and crew. Now go back and tell the college sailor that, upon further review, you have an answer for them.

Get an iphone and a waterproof case. Get iRegatta app and sail to all directions so you register your polar for the current wind speed. If you want to know your optimum tacking angle, look at the VMG polar.
It works if wind direction and speed are fairly constant, which is probably not so common though...

90° is pretty optimistic for cats in my opinion. (Or I'm doing something wrong...)

Cool app. Pair it with with some Bluetooth waterproof headphones and you've got yourself a fun little training app.

And this matters...why? Can we measure it on the water? ie, do we say,

Well, we are only at 87 degrees, we'll have to wait another 3 degrees to tack...

No, we don't. We tack when we think we can make it, and I have no idea exactly what angle that is. When it looks right, I tack. That's why the guys with the most experience do it better than the newbs, they know what looks right.

It's all well and good on a chalkboard, as this college sailor is probably used to being shown, but in reality, who cares exactly what the angle is?

We don't cary enough electronics (like the AC guys do) to make it a worth while number to know, or measure or present that info to us, on board, so what's the point? When it looks good, tack. If it didn't work, tack again.

The biggest use for me of knowing the

tacking angle

is when I race in a Pt-to-Pt race (

distance

) and am using a compass. This knowledge allows me to quickly calculate which tack (port or starb) is the

favored

tack. Also it is useful to determine if you have a

tide set

effecting your progress

I find that I my tacking angles are between 90*-100* aproximently .... sometimes 110* if I was pounding through some serious wave conditions ... or against a tide. On

flat

water in a steady medium breeze I would sometimes approach 75*-80* ....

But usually I have found you need to be working w/ a compass in order to make use of

tacking angle

knowledge ... and on a catamaran on a short

buoy

type course you don't have the time ... or a compass. (I'm a POOR traditionalist ... no fancy computerized

aids

... no

apps

... just a hand bearing compass, a stop watch, my eyes ... and my brain/mind for calculations)

Harry Murphey
H18Mag/P19MX

Everyboby hold up a second. Why is no one calling Pete out for being a week early for April Fools? College chick on his boat... RIIIIIGHT...

Mike

Because it's what monohull sailors use to compare their boat to others. At 3 knots, 0.5 degrees higher is a big deal.

Why? Because I'm training them (a guy and a girl) that the forward position is the skill position on an F16. They have to pull all the strings, call the lay lines, pick shifts and tactics; as well as run the clock. I figure if I'm buying lunch I oughta get my money's worth.

Crap, Jake. Got Soda in my nose again thanks to that... man it burns..

Just take her out on a windy/wavy day. After you pass the first powerboat, she will forget all about that nonsense...

Mike

I haven't forgotten how dismal my racing history is! I was hoping to learn from these people. She thinks tacking angle is important, I'm going to find out why.

But... I'm beginning to suspect no one knows!

Tacking angle is good for judging course laylines and some strategy.. Shorter time on the course usually keeps you ahead of competition (unless you're pinching, which is slow death) if all else is the same.

Let her drive and she'll figure out that tacking angle isn't nearly as important as tacking speed

Jake told you why.

Sounds like she's a pokey boat sailor, and is thinking like one in reference to multis. Different thought process.
It's just a huge variable on multihulls that use apparent wind. The faster you go the less the angles are.

Slight variation in subject: can you sail your A cat at 70 degrees(without pinching)?

I've never kept track of it ( just now getting a tack tick set-up on the A) and I'd be guessing if I gave you an answer. I'm sure there are plenty who could tell you. Bob Hodges and Bob Curry ( as well as others) have done alot of documenting and tuning with GPS and could probably give you an educated answer.

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