Tacking in light winds?

[Tupaia]

A simple tip if you have a GPS on board, I am sure you do. Set a WP directly to windward but a long distance away say 100Nm. Adjust your sails and angles to obtain the highest VMG to WP (Velocity made good to way point). Allow the boat to settle after each adjustment and gradually you will build up a pattern for the best settings. Remember that the settings will only apply to that particular wind speed. Because the WP is fixed relative to the earth it will also show you if you are going forwards, backwards or just side to side.

[danstanford]

Originally Posted by Tupaia

A simple tip if you have a GPS on board, I am sure you do. Set a WP directly to windward but a long distance away say 100Nm. Adjust your sails and angles to obtain the highest VMG to WP (Velocity made good to way point). Allow the boat to settle after each adjustment and gradually you will build up a pattern for the best settings. Remember that the settings will only apply to that particular wind speed. Because the WP is fixed relative to the earth it will also show you if you are going forwards, backwards or just side to side.

Great idea!

On the same path, most wind instruments will have a setting for 'VMG to wind' which works for this purpose and even gives you a negative but still relevant number when going downwind.

[flee27]

What lake do you sail on?

To add to the other great advice already given. When you are tacking in light air, start the end of each tack a little further off the wind then the course you desire. Being a little further off the wind with the sail less trimmed you will build speed quicker and hopefully not stall the boat. As speed builds slowly head upwind while carefully trimming the sails. Balancing speed and pointing as to not stall the boat is challenging and imperative for upwind performance in light airs.

As others have said light air sailing is the most challenging sailing there is generally. And if your lake is like most you also have really shifty wind to further complicate the condition.

Enjoy the process. The fact that you always can learn when sailing is part of what makes it such a great sport.

Foster

[s/v Jedi]

Tacking upwind in light weather is where the art of sailing is demonstrated. It won’t be mastered easily, I trained years and years in a Laser trying to win even a local race but there’s always someone better around

Seriously, you will be astonished when you see an experienced competition sailor take your boat upwind in those conditions. Try to find some and learn the skill. It’s more of a feeling you need to get than a technique explained in a book. If you are in a position to try dinghy sailing (Sunfish, Laser etc.) then I highly recommend it because it will be a much quicker (and steeper) path

[Tupaia]

Originally Posted by danstanford

Great idea!

On the same path, most wind instruments will have a setting for 'VMG to wind' which works for this purpose and even gives you a negative but still relevant number when going downwind.

Either way works but not so good in very light winds when you are learning as wind instruments tend to be less stable.

[thomm225]

Never use wind instruments to tack with.

That's totally the wrong way to learn.

Know the basics of tacking then go out and sail.

Sail a few miles tacking every couple 100 yards or so

You will then learn especially if you do it in varying wind conditions.

When its super light and you aren't moving sometimes you can backup to complete the tack.

It's like riding a bike.

Hard to explain but practice makes perfect

[Canopus]

Originally Posted by danstanford

I think you have your vectors mislabeled in your sketch. On a close hauled course a good boat well trimmed will sail to about 45 degrees to the true wind giving apparent wind of somewhere around 30 degrees.

I wondered about this but I really don't think so for the following reasons.

1. The boat knows nothing about the TRUE wind (unless stopped). Once it moves, it only knows about the APPARENT wind.

2. The wind vane on top of the mast indicates where the APPARENT wind is - not the TRUE

3. I've been taught to keep the wind indicator outside of the square markers (about 90 deg to each other) and these markers are for 45 deg relative to the APPARENT wind
[edit made to correct this]

4. If a particular boat's sail luffs when 45 deg to the wind, this must refer to the APPARENT wind since this is when the aerodynamic stall occurs.
[edit made to correct this]

I think there is a small confusion/ambiguity in general sailing literature I'm addressing here. Nothing I'm addressing will change how one sails in practice - when close-hauled you'll adjust sails until they are near luffing.

What I am suggesting is an explanation of how if the TRUE wind is (for example) from the North, your tacks may not be Northeast and Northwest, but might be much closer to East and West because these are the courses needed to tack into the APPARENT wind - the APPARENT wind can change dramatically on different tacks - even if the TRUE wind doesn't.

This is consistent with my own experience that motivated my interest in this question where I was tacking in light winds and for the most part was only moving laterally.

[flee27]

Originally Posted by Canopus

I wondered about this but I really don't think so for the following reasons.

1. The boat knows nothing about the TRUE wind (unless stopped). Once it moves, it only knows about the APPARENT wind.

2. The wind vane on top of the mast indicates where the APPARENT wind is - not the TRUE

3. I've been taught to keep the wind indicator outside of the square markers (about 90 deg to each other) and these markers are for 45 deg relative to the TRUE wind

4. If a particular boat's sail luffs when 45 deg to the wind, this must refer to the TRUE wind since this is when the aerodynamic stall occurs

I think there is a small confusion/ambiguity in general sailing literature I'm addressing here. Nothing I'm addressing will change how one sails in practice - when close-hauled you'll adjust sails until they are near luffing.

What I am suggesting is an explanation of how if the TRUE wind is (for example) from the North, your tacks may not be Northeast and Northwest, but might be much closer to East and West because these are the courses needed to tack into the APPARENT wind - the APPARENT wind can change dramatically on different tacks - even if the TRUE wind doesn't.

This is consistent with my own experience that motivated my interest in this question where I was tacking in light winds and for the most part was only moving laterally.

Not arguing.

In your statements above you correctly state that the boat doesn't know TRUE wind while moving. Then in #3 you state the markers are for 45 deg relative to TRUE wind. These markers are 45 degrees relative to APPARENT wind as you stated in #1 and #2. Correct?

The take away/experience for me is/has been you can not focus on sailing 45 or some other degrees off the wind in light airs. You have to do the right things to sail as close as efficiently possible in lights airs, in your situation. This will be different for different boats in different conditions. Angles are only relevant to gauge you own progress in a set of consistent conditions.

best

Foster

[Canopus]

To help with context, here are some Navionics tracks from recent sails. One shows the lateral fight I had to avoid a hazard and to position myself so I could do long tack towards the marina to the SE (where the TRUE wind was coming from.)

The other is from the other day when the winds were much stronger and tacking was more like I expected.

[Canopus]

Originally Posted by flee27

Not arguing.

In your statements above you correctly state that the boat doesn't know TRUE wind while moving. Then in #3 you state the markers are for 45 deg relative to TRUE wind. These markers are 45 degrees relative to APPARENT wind as you stated in #1 and #2. Correct?

The take away/experience for me is/has been you can not focus on sailing 45 or some other degrees off the wind in light airs. You have to do the right things to sail as close as efficiently possible in lights airs, in your situation. This will be different for different boats in different conditions. Angles are only relevant to gauge you own progress in a set of consistent conditions.

best

Foster

Yes - I meant 45 to TRUE in point 3 - I'll fix it. Thanks

[danstanford]

Originally Posted by Canopus

I wondered about this but I really don't think so for the following reasons.

1. The boat knows nothing about the TRUE wind (unless stopped). Once it moves, it only knows about the APPARENT wind. You are correct.

2. The wind vane on top of the mast indicates where the APPARENT wind is - not the TRUE You are correct.

3. I've been taught to keep the wind indicator outside of the square markers (about 90 deg to each other) and these markers are for 45 deg relative to the TRUE wind This is correct though the angle should be closer to 65 degrees for a normal cruiser type boat. as noted before, this is indicated relative to the apparent wind not the true

4. If a particular boat's sail luffs when 45 deg to the wind, this must refer to the TRUE wind since this is when the aerodynamic stall occurs. See your #1 above which is true, the boat and sails only respond to apparent wind. For example, if you are sitting still apparent and true are the same but the faster you go the more they diverge but the sails are still responding to the wind they feel which is the apparent.

I think there is a small confusion/ambiguity in general sailing literature I'm addressing here. Nothing I'm addressing will change how one sails in practice - when close-hauled you'll adjust sails until they are near luffing. The other technique is to set the sails for something between a broad reach and close hauled and then steer the boat to the sails. Once you have some speed built you can trim closer and head up closer to the wind.

What I am suggesting is an explanation of how if the TRUE wind is (for example) from the North, your tacks may not be Northeast and Northwest, but might be much closer to East and West because these are the courses needed to tack into the APPARENT wind - the APPARENT wind can change dramatically on different tacks - even if the TRUE wind doesn't. Apparent wind will only change in this scenario if you are going different speeds on the two tacks (which might be absolutely true). Apparent is the sum of the two vectors. The better you learn to trim and sail the closer to NE and NW you will sail.

This is consistent with my own experience that motivated my interest in this question where I was tacking in light winds and for the most part was only moving laterally.

Some of what you write is correct and some is wrong and I am going to write inside your post above what these are.

Building speed by sailing east-west from your example can be step one toward learning to sail better as it creates apparent wind which will be stronger than the 5 knots true you have to work with the more close hauled you sail.

[Canopus]

Originally Posted by danstanford

Apparent wind will only change in this scenario if you are going different speeds on the two tacks (which might be absolutely true). Apparent is the sum of the two vectors. The better you learn to trim and sail the closer to NE and NW you will sail.

The apparent wind is the result of combining the TRUE WIND and the boat's velocity vector. If the boat changes direction, it's vector will change, hence the APPARENT wind changes.


And this is getting to the heart of the issue: because the APPARENT wind changes, trying to tack 45 degrees relative to the APPARENT wind means when switching tacks, the course can change significantly more than 90 deg.

Put another way, I've had instructors suggest heading about 90 deg off a current tack to get on the next tack - but this can be very wrong. Obviously you do what needs be done to do the best close-hauled tack and not be obsessed with gauges etc.

Many thanks for your comments.

[ChrisJHC]

Many boats (including mine) can point higher than 45 degrees. For example, mine starts to luff significantly at 35 degrees.

When I’m tacking, I find it best to do a 90 degree tack and then, when the boat picks up speed, gradually bring her to around 40 degrees.

The actual angle to the wind I can hold depends on a range of things, including how much sailing into the swell slows me down.

And one final thing to confuse the OP: many boats find they can hold a closer angle to the wind on one tack rather than the other!

As many have said, you’re always learning, particularly heading upwind in light airs.

[s/v Jedi]

The first time you discover that your boat can sail 10 degrees closer to the wind is magic, I still remember it.

Turn the bow a little away from the wind, let the sheets out a little bit, make the boat heel and pick up speed. While you feel the wind heeling the boat and providing drive, start inching closer to the wind and bringing in the sheets, making sure not to overdo it which you feel from losing wind pressure in the sails and losing heel. The boat should increase heel when steering up a bit more.

You will take it too far and lose it: the trick is to get to feel where to hold.

Also, I get the idea that this light air sailing is considered a static thing, but it isn’t: you change course all the time, trying to guess the next little windshift or puff and anticipate on it.

If your instruments can show laylines, check that you can at least sail those lines.

[Cwens]

A sporty boat with good sails properly trimmed, sailing in nice conditions (say 10 knots and flat water) ought to tack through less than 90 degrees (i.e. true wind less than 45 degrees off the bow, apparent wind somewhere around 30).


Older, beat up sails, not ideally trimmed, lighter winds, choppy waves, plumper, less sporty boat, you're not going to see those angles.



But even so, if you can't sail higher than 45 degrees of apparent wind angle, something's not set up correctly.