Long tacks or short

[MM5AHO]

I've had the argument too many times.
Is it better to do more shorter tacks heading more towards the upwind mark (passage racing), or longer tacks?
Does it actually make any difference?

 

[sarabande]

assuming no wind changes in direction and strength, every tack you put in adds one or two minutes through loss of speed, need to re-adjust boat and sails, so the fewer the better, in theory.

OTOH a single tack could led to a disastrously wasteful overstand.

However, with variable wind speed and direction, you need to look at where and when the freeing wind will benefit you. Tack towards the freeing wind.

 

[savageseadog]

Every tack costs time so there has to be a reason to tack, these could be:

1) Better wind or tide
2) To cover a competitor's tack or take wind
3) To obtain an advantage at a mark
4) To avoid being covered or being tacked on
5) To make a mark
5) To fool the competition

In general the risk with long tacks is of being stranded out on the wrong side of the race area. A good general rule all things being equal.would be to keep your boat between the competition and the next mark if at the front. At the back it may pay to try something different

 

[flaming]

No wind is ever free of shifts. If you are standing on and not tacking on the shifts then it has to be be for a good reason.

That reason could be that the shifts are small and frequent, so tacking on them does not gain back the distance lost by tacking.
It could be that you want to sail to one side of the course because you expect a more significant shift to come through and make much more difference to the overall time.
It could be that one side of the course is favoured due to tidal considerations.

Ignoring forecast wind changes, and tidal advantages (i.e. assume there isn't any) If you go hard to one side of the course and only do 1 tack, you are at risk of the following.

A bad windshift that favours the other side.
Miscalculating the layline and overstanding the mark, resulting in unnecessary distance sailed.
Wind dying off on your side of the course.

Basically, to decide to 1 tack a beat I would have to be very confident that the side I was choosing was DEFINITELY the favoured side. But then most of my racing, and therefore thinking, is short course many races in a series type racing. In series racing actually winning each race isn't the aim, avoiding bad results is the aim, so unless 100% sure go up the middle and if left is favoured then at least you beat all the boats that went right. In that type of racing being the furthest left, or furthest right, boat is generally considered to be a risky move.

But when passage racing, especially if your aim is just to win this one race, I think that your criteria for "banging a corner" has to be lower. If you think it's likely, rather than if you are 100% sure then you should probably back your feeling. Maybe hedging a little bit if you find yourself out on your own, and coming back before you have gone all the way to the layline to keep a little in the bag.

That said, I suspect there are just as many races where the favoured side changes as the race progresses as there are races where banging the corner is definitely the fastest way.

 

[Bav34]

Something not mentioned above but vital is the skill of the crew and type of boat.

I have seen helmsmen who put the helm hard over to start a tack ... a good brake, crew who aren't in the right place, crew letting genoas go too soon or too late, no winch handles in place at the right time, helmsmen sailing too low, large genoas having to be cranked in against the (now) beam wind as the helm now pushes the tiller the other way to get up to wind ... and stalls.

The list of errors is endless whereas on a well crewed boat the tacking losses can be minimal.

 

[Birdseye]

I'll likely get shot down in flames but here goes.

Tacking always loses you some boat speed because there is a brief time when the boat is not under full drive. OK you can recover that boat speed by being little more free immediately after a tack but that costs you distance to windward. So in reality there is always a loss in tacking even in the lightest boat with the slickest crew. There are two laylines from an upwind mark and in a steady wind and tide, I cant see any way in which it wouldnt be better for a boat inside the laylines to sail to one of those lines , tack and then run up it to the mark.

If the wind isnt steady then there is a judgement call whether to tack or simply to respond to the change with trim or heading. Same if there is an element of match racing in the situation but ignoring the rest of the fleeet and without permanent changes in wind or tide, the minimum number of tacks just has to be the fastest

 

[Keen_Ed]

I've had the argument too many times.
Is it better to do more shorter tacks heading more towards the upwind mark (passage racing), or longer tacks?
Does it actually make any difference?

Completely depends on the boat.

Lots of rocker, fast tacking, slow boat - tack more
Less rocker, slow tacking, fast boat - tack less.

 

[flaming]

I'll likely get shot down in flames but here goes.

Tacking always loses you some boat speed because there is a brief time when the boat is not under full drive. OK you can recover that boat speed by being little more free immediately after a tack but that costs you distance to windward. So in reality there is always a loss in tacking even in the lightest boat with the slickest crew. There are two laylines from an upwind mark and in a steady wind and tide, I cant see any way in which it wouldnt be better for a boat inside the laylines to sail to one of those lines , tack and then run up it to the mark.

If the wind isnt steady then there is a judgement call whether to tack or simply to respond to the change with trim or heading. Same if there is an element of match racing in the situation but ignoring the rest of the fleeet and without permanent changes in wind or tide, the minimum number of tacks just has to be the fastest

Well you asked for flames....

Your argument is absolutely true if, and only if, the wind was exactly steady and the sailor was capable of absolutely nailing that layline from a long way away. After all, if the beat is 1 mile, then you need to be able to hit that layline from about 2/3 of a mile from the mark. If you can do that on a lake with a constant wind every time you're a better sailor than me. Add in tide, wind bends, shifts etc that are the actual reality, and the odds of nailing that layline are extremely small. On the times that we've ended up one tacking a beat due to traffic etc I think we've hit that layline once. And once you've overstood you've just thrown distance away, understand and your plan to limit the number of tacks is shot and you might as well do the tacks in a more sensible place that doesn't open you up to a bad windshift ruining your race.

But that totally and utterly ignores the main reason you tack. Wind shifts. The most stable wind I've ever sailed in was oscillating through a mere 5 degrees. I suggest taking the numbers from your boat - TWA achieved, speed and distance lost through a tack (the last will be a guess, but most people would think somewhere around 5 boatlengths per tack to be reasonable, then see how long it would take you after a tack sailing on a 5 degree lift to get back that 5 boatlengths lost in the tack. I suspect you'll be surprised.

Failing that, register at SailX.com and see how rarely one tacking the beat every works...

 

[Birdseye]

Well you asked for flames....

Your argument is absolutely true if, and only if, the wind was exactly steady and the sailor was capable of absolutely nailing that layline from a long way away. After all, if the beat is 1 mile, then you need to be able to hit that layline from about 2/3 of a mile from the mark. If you can do that on a lake with a constant wind every time you're a better sailor than me. Add in tide, wind bends, shifts etc that are the actual reality, and the odds of nailing that layline are extremely small. On the times that we've ended up one tacking a beat due to traffic etc I think we've hit that layline once. And once you've overstood you've just thrown distance away, understand and your plan to limit the number of tacks is shot and you might as well do the tacks in a more sensible place that doesn't open you up to a bad windshift ruining your race.

But that totally and utterly ignores the main reason you tack. Wind shifts. The most stable wind I've ever sailed in was oscillating through a mere 5 degrees. I suggest taking the numbers from your boat - TWA achieved, speed and distance lost through a tack (the last will be a guess, but most people would think somewhere around 5 boatlengths per tack to be reasonable, then see how long it would take you after a tack sailing on a 5 degree lift to get back that 5 boatlengths lost in the tack. I suspect you'll be surprised.

Failing that, register at SailX.com and see how rarely one tacking the beat every works...

Flames? That isnt even a smoulder!

I never have understood the "tack on a windshift" when the windshifts are 10 15 and maybe even 20 degrees. Just suppose you are laying the mark hard on the wind and the wind shift frees you off by 10 degrees. Do you tack then or just offer prayers of thanks and adjust sails accordingly. Or if it heads you by 10 degrees do you then tack through 80 to 90 degrees? How does that get you to the mark faster?

I can see what you are getting at with the comment on overstanding but you lose just as much if not more by sailing on the other tack.

 

[lw395]

There are two very simple rules I've heard:
Short beat, Oscillating wind: Always be on the lifted tack.
Long beat, where the wind will shift over the duration e.g. Passage race, Always be on the Making tack.

There are exceptions of course, like wind bends due to a shore, or uneven tide across the course.

For the best explanation of the gains of tacking on shifts, read 'Winning in One Designs' by Dave Perry.

 

[flaming]

Flames? That isnt even a smoulder!

I never have understood the "tack on a windshift" when the windshifts are 10 15 and maybe even 20 degrees. Just suppose you are laying the mark hard on the wind and the wind shift frees you off by 10 degrees. Do you tack then or just offer prayers of thanks and adjust sails accordingly. Or if it heads you by 10 degrees do you then tack through 80 to 90 degrees? How does that get you to the mark faster?

I can see what you are getting at with the comment on overstanding but you lose just as much if not more by sailing on the other tack.

Well obviously a wind shift when you are already on the layline is no good to you.

But then that's what we're trying to tell you. In an oscillating breeze, if you go to a corner and do 1 tack, and I play the shifts up the middle doing 10 tacks, I will pop out well ahead at the first mark.

If you're in an oscillating breeze, a tactical plan that sees you on the layline with the wind due to shift before you get to the mark is a poor plan.

 

[bbg]

Birdseye, as usual I agree with flaming. Your example of being on the lay line and seeing a wind shift is exactly the reason why you should not get to the lay line early. If you are laying the mark and get a lift, you have over stood.

One thing that hasn't been mentioned is hitting the lay line early if you are not in front. If you are in front and you hit the lay line from half a mile away and the wind doesn't shift, good for you.

But if you are not in front, you can expect someone to tack in front of you and give you dirty air. Then you are not laying the mark any more and will have to tack again anyway.

 

[Birdseye]

Well obviously a wind shift when you are already on the layline is no good to you.

But then that's what we're trying to tell you. In an oscillating breeze, if you go to a corner and do 1 tack, and I play the shifts up the middle doing 10 tacks, I will pop out well ahead at the first mark.

If you're in an oscillating breeze, a tactical plan that sees you on the layline with the wind due to shift before you get to the mark is a poor plan.

If you are bang in the middle of a windward leeward laid course and with a well organised crew I can accept what you are saying. But my racing is round channel markers where the upwind mark is rarely directly upwind, where there is usually a 2kn tide plus waves and an NHC level crew. Then I simply dont think that you can make a "tack on a windshift" rule. If anything there is usually a making tack from the downwind mark and tacking on a windshift can easily have you sailing away from the mark.

Simple vector maths suggests that it will only ever pay if you are in the middle of the laylines and tracking either side of the centre line. If the wind is oscillating significantly, and even then its a trade off of tacking distance lost against distance gained. But its an interesting question - if I could get into SailX I'd have a play. Their program obviously has a mathematical model of boat performance at various wind angles, something which I might once have worked out for myself but am long past being able to do now.

Meantime "tack on a windshift" is a bit like lee-bowing. One of those things I often hear but am not sure are correct.

 

[bbg]

As flaming says, it is not a hard and fast rule. The points you make are really related to whether you are truly sailing to windward (if it is a fetch there is no point tacking on a wind shift) and how much you would lose in the tack. You can do something about the latter issue - and if you aren't, you can be sure that someone else in your fleet is.

 

[lw395]

If you are bang in the middle of a windward leeward laid course and with a well organised crew I can accept what you are saying. But my racing is round channel markers where the upwind mark is rarely directly upwind, where there is usually a 2kn tide plus waves and an NHC level crew. Then I simply dont think that you can make a "tack on a windshift" rule. If anything there is usually a making tack from the downwind mark and tacking on a windshift can easily have you sailing away from the mark. ......

Unless it's a fetch, tacking at the right time wrt the shifts can still help.
Obviously there are limits, you don't want to pass up a knot of favourable tide for a small lift.
But OTOH, if you should be tacking for clear air or other reason, timing that with the shifts can help hugely.
At my old club, the fastest route to the first mark very often did have you initially getting more distant from it, it was more important to get to the right tide than to make direct progress to the mark.
Usually. People can always take a chance and win the odd race by going the other way. But most series are not won like that.

 

[Ingwe]

Birdseye I think you have got hooked on the "tack on a windshift" phrase, what is really meant is that you need to be in phase with the wind oscillations (on the lifted tack / gybe) for as much of the beat / run as possible.

To do this you need someone on board taking note of the wind oscillations pretty much from when you leave the dock so that they can build up a pattern of what the wind is doing on the day, which will normally be a combination of oscillations as well as a persistent shift over time. With practice they can then start to predict which way and when the next shift is going to be and how many oscillation phases there should be on the next leg of the course, once you know that you then start factoring in tide / land effects / positing against other boats to work out what is going to be the optimal way up the next leg of the course.

 

[harstonwood]

It's an interesting question! In a race we did on Saturday (55miles across Irish Sea) with the destination being bang into wind .....the forecast was for the wind to back, and tides to reverse roughly 4hours into the race. Tide was late, wind backed 35 degrees. Anyway we made it on one tack, but I spent about 6 hours pondering this vey question!
Our ais trace

 

[Birdseye]

I suppose thats an illustration of what I was trying to say. Had you tacked on the wind shift you would have ended up going at right angles to the course you needed. Question is whether you might have been quicker had you gone onto port soon after start.

 

[harstonwood]

Indeed
The one boat that did Starboard tack after start got marooned in light airs (forecast)
The rest of the fleet (26) started on port ....we started starboard but tacked three mins or so after start
My plan was to do a short starboard tack when the tide changed, (mid Irish Sea) but for some unexplainable reason it turned an hour late....by then the wind had started to back and I could see, with the tide now running north we would make Holyhead on port, with an improving angle.
All a guess really!