Tacking angle

[macbeth]

What is an acceptable acceptable tacking angle ? i.e. you are heading 0 magnetic degrees North against the wind. When you tacked would you expect to be 90 degrees, or 100, or 110, etc., The best I can do with my inside track is 110 degrees. Is that good, average, or awful ?! I have not measured using the outside track, but it will be larger I guess. By about how much should it be ?

[Stu Jackson]

Depends on the boat and how it is sailed. That's the stock answer.

I'm happy with 110 on ours inside track (all I got!).

If I can get it to 100, then it's easier to get a new helmsoperson to do the math in their head, then we fall off from there.

[monte]

It depends on the boat and current. We aim for about 90 degrees but with adverse currents and lighter winds it might be closer to 120 degrees. Obviously pointing higher (less angle) is more direct but speeds will be slower so it's a bit of give and take to find the groove for your boat.

[savoir]

There is no correct answer to that question. Boats vary so much.

110 degrees is bad for a mono but good for a cat.

[monte]

I'd say 90 degrees is about average for a cat or mono without too much adverse current. Both will suffer if heading into too much current.

[brownoarsman]

I've been struggling with this too. There is another thing to consider in the argument too which is leeway. I have a broad tacking angle on the boat due to the huge amount of windage from the standing headroom cabin, but my leeway is basically zero thanks to my 5' draft on 28 feet, so look at COG as well in evaluating your boat.


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[barnakiel]

Originally Posted by macbeth

What is an acceptable acceptable tacking angle ? (...)

(...)

180 is only so-so.

It is nice when a cruising boat can make it within 90 in flat water.

Then again, if your boat is fast enough, 179 is a fair limit.

b.

[barnakiel]

I have looked up your design. On the paper, you should be able to be well within 90 degrees. Sails condition, sails trim, boat bottom condition, (to much) cruising gear, too big a dodger, etc., typical culprits.

b.

[cabo_sailor]

In addition to what's been said, your sail rig type plays a part. My boat is true cutter rig as opposed to a staysail rigged sloop. In all the cases I am aware of, the sloop will point closer to the wind than I and thus have a smaller tacking angle.

I also learned that at least on my cutter, if I have too much foresail up the tacking angle becomes truly abysmal. Rigging tension, keel design, load trim are all factors. You can experiment but getting ahold of an owners group may be your best starting point.

Regards,
Rich


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[GILow]

Don't forget sail condition. We improved by ten degrees with the new sails. Thanks SVTotem!

Matt


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[44'cruisingcat]

Originally Posted by savoir

There is no correct answer to that question. Boats vary so much.

110 degrees is bad for a mono but good for a cat.

Faster boats will drag apparent wind forward by more, so sometimes faster boats will tack through bigger angles.

As an example - if you were able to sail at windspeed at 45 degrees apparent, (we can nearly do this in around 10 knots wind) you'd be "tacking" through 180 degrees. Whereas a very slow boat might sail at the same 45' apparent and only tack through 95 or 100.

We sail at around 30' apparent, and tack through about 100'. We could point higher and tack through smaller angles, but our VMG would be lower.

[FamilyVan]

I'm in the neighbourhood of 100-120, if I can even get her through the wind- but a Niagara 31 should far out perform my boat.

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[macbeth]

Originally Posted by FamilyVan

I'm in the neighbourhood of 100-120, if I can even get her through the wind- but a Niagara 31 should far out perform my boat.

Unfortunately, I'm on a pension, and couldn't afford a new Genoa when the old one was REALLY WORN OUT ! So I found a used on, but of course, it's not cut really to the shape needed. Oh to be a millionaire !

[thomm225]

A racing catamaran ( Nacra F-17 or Nacra 6.0) can sail maybe 30-40 degrees off the wind upwind if that is what you mean by "tacking angle?"

Not sure on monohulls, but my next boat may be an Ericson 35 Mk III which draws 6"2" and has a 29' LWL. I'm thinking it will sail pretty darn close to the wind also.

http://sailboatdata.com/viewrecord.asp?class_id=1979

your boat will not point as well as the Ericson (or a racing beach cat with almost a 4' daggerboard and moving at 15 knots plus):

see why below:

http://sailboatdata.com/viewrecord.asp?class_id=1677

[2Wind]

The experienced need read no further....

To the less experienced read on:
1. When this is discussed always determine the basis for the measurement.
2. If only using your wind instrument at your guide, first consider if you are reading apparent wind angle of true wind angle.
3. Understand there are sources of error in the equipment. For instance, the wind vane sends only apparent wind angle data, with true being calculated instantaneously using vectors derived by your speed log (another potential source of error) and the anemometer (potential error).
4. You may "tack through" 60-65 degrees apparent, but this may be 90+ true.
5. If you tack displaying the true wind angle, you wil appreciate the difference and this will reflect you actual tacking angle, but only withing the medium i.e. it assumes the water in which you are sailing is not actually moving itself (as in current), and that you have no leeway (which will be false).
5. Your track on a GPS based plotter reflects "actual and true" tack angle (inclusive of leeway and current) as it references to the planets surface not the medium (water on which you are sailing).
6. True "performance" to windward is best appreciated by understanding the concept of velocity made good VMG or course made good CMG. which take into consideration the various factors that influence just how quickly you are making your mark directly upwind. This is more complex than it seems.
7. In its most simple form, as in the VMG display on the wind instrument, it relates to boat speed at differing angles of attack (consider that although you may potentially sail a shallow angle to windward, you will slow down in doing so). This is pure but simple trigonometry. Essentially, a given boat's VMG will be optimal at an angle that is usually greater than it's best angle of attack. This will be further amplified by leeway which increases the closer to wind you sail.
8. In more complex performance modelling, as in competitive racing, the VMG and CMG systems will also take into consideration issues of leeway with varying application of underwater appendages on offer, drag, tide and current, not to mention the the various imponderables that relect the the art of racing that include wind shear, wind shifts, knocks and lifts etc.
9. Finally, and to expand on 44C's comments, one needs to reflect on just how much boat speed will influence apparent wind angle and one's perceptions of what is a "good angle". When up wind, the faster you can go the more the apparent wind comes forward ultimately requiring course change to leaward to avoid stalling. Your true course will be more off the wind but as your speed is so advantageous, it is irrelevant in terms of making the mark quickly. Remember very fast boats like the AC72's actually sail to windward (apparent) even on a (true) downwind leg, potentially being hard on the wind where ever they go.