Planning a short journey to windward, with a backing wind

[GILow]

Hi Cruisers,

One of my favourite destinations is 35 miles due West from our home port.

The prevailing wind pattern causes me a dillemma. Often it seems that I am faced with a Westerly wind in the morning, backing to a South Westerly in the afternoon, say around 14:00 hrs. Wind speeds are often around the 10 to 15 knots range.

If I set off on a starboard tack, I am going to be well south of the required course and when the wind shifts I should have a decent reach to my destination on the port tack. This works in theory, but of course, as the wind slowly backs during the day, I have to decide when I am pointing too far to the South and it is time to tack.

Otherwise, I can set off on a port tack, and as the wind slowly backs, I keep adjusting my course to remain pointing, and do the whole journey on a port tack. At least in theory. In practice, if the wind shift is late, or I end up too far to the North, I am faced with a series of tacks to the South to regain my course at some point.

So, with option one, I feel I have a better second leg, as our boat, like many, enjoys a good reach more than pointing. But I think it is a longer journey on average and it requires some concentration on WHEN to tack. Option two is the kind of no-brainer option where I just keep pointing and hope the wind has backed enough by the time I get to the destination that I won't have to throw in an extra tack or two to make my way back down South.

So with an older heavy cruising cutter, that can point ok up to around 50 degrees to the true wind direction on average, that cruises between 5 and 6 knots, what would you do? Any rules of thumb to apply such as breaking the journey down in to time blocks in each wind condition?

Oh yes, I should acknowledge that any sensible cruiser, given the option, would wait for more favourable wind conditions, but sadly, being an office worker with limited time to sail, I cannot afford to be that discerning.

Matt

[StuM]

If you start on the starboard tack, you are going to be constantly knocked further off course until you tack. That second leg is going to be looong.

If you start on the port tack, you are going to be constantly lifted towards your destination. Any second tack will be much shorter in this situation.

Assuming that your target is initially dead upwind, I'd take the second option every time.

[JPA Cate]

StuM,

Nicely stated. And here i was, thinking about waiting for the favorable wind.......

Matt:
Stu's right, I think. You'll be low of your course at first, but then as the wind backs, it will lift you; last couple of tacks should be short, if required.

[GILow]

Thanks StuM.

Hmmm, sounds clear enough when you put it that way... I just wonder what happens if I tack early enough when starting on the starboard tack? Maybe a short tack to the South West at the start, before the wind starts to back? The head back to the North West and sail the arc dictated by the backing wind... That way I would not be faced with trying to make my way South at the end of the journey.

I reckon this should be possible to model mathematically. Something to try over the weekend.

Matt



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[meirriba]

If you had some racing experience it would be a clear decision.
Port tack and enjoy the lifts of the backing wind.

[canyonbat]

We just spent a week in San Diego sailing with a professional racing helmsman. His advice was "always sail to the new wind". Following this advice, you will sail on the starboard tack until you reach a point where you can make your destination on a single port tack. If the wind switches early, you tack early, if it is delayed or doesn't switch at all, you tack later.

[GILow]

Originally Posted by canyonbat

We just spent a week in San Diego sailing with a professional racing helmsman. His advice was "always sail to the new wind". Following this advice, you will sail on the starboard tack until you reach a point where you can make your destination on a single port tack. If the wind switches early, you tack early, if it is delayed or doesn't switch at all, you tack later.

This is very interesting. If simply because it underlines the fact that there are two ways of skinning this particular cat. I am absolutely going to model this one, mathematically is proving hard so it will probably have to be computationally.

Your racing helmsman is suggesting what I feel is the "harder" but potentially more rewarding option. Preliminary calculations so far (sitting up in bed at 3am with pen and paper) suggest his/her solution to be the fastest IF you make a good call on the wind shift. But it is a chaotic solution and quickly diverges from optimal if you tack to early or too late, more so if you tack too late.

StuM's solution is more stable, and certainly the safer bet as the solution does not diverge nearly as badly. So typically it looks like it will be faster unless you are really concentrating on the timing.

Meirribas comment is illogical. If I did not have any racing experience (which I do, thanks, and pretty darn successful too, you don't get your boat name engraved on 110 year old trophies if you can't sail) I would probably not be trying so hard to calculate the optimum solution. And it's not just racing sailors who'd like to make the quickest journey, the shops close pretty early where I am heading. I have to make landfall before last orders.

Matt

[meirriba]

Originally Posted by canyonbat

We just spent a week in San Diego sailing with a professional racing helmsman. His advice was "always sail to the new wind". Following this advice, you will sail on the starboard tack until you reach a point where you can make your destination on a single port tack. If the wind switches early, you tack early, if it is delayed or doesn't switch at all, you tack later.

This is correct for a a shift normally encountered in a normal race around the cans.
Ask your friend what will be his strategy for a long race leg where the forecasted wind lifts his boat to the top mark without tacking.

[canyonbat]

Originally Posted by meirriba

This is correct for a a shift normally encountered in a normal race around the cans.
Ask your friend what will be his strategy for a long race leg where the forecasted wind lifts his boat to the top mark without tacking.

I guess it depends on the likelihood of a wind shift early enough to make it work. Ride that port tack too long and you are faced with a beat to get back to the mark. Ride that starboard tack too long and the worst you are facing is a speedy reach back to the mark.

Of course, if the decision was easy, all the boats in a long race would choose the same exact course!

[MarkJ]

I think the main point is that the boat is a heavy old cruising boat, not a racer at the helm, but someone who has done this trip often so knows the local winds.

I would start on the Starboard tack and take your southing early. As soon as the wind begins to start changing tack onto port.

It must be a sea breaze effect when the land builds up heat so you know what time the change begins to occur, say midday, so you want to be on your port, lifting tack by then. Remember your heavy cruising boat suffers more speed loss every time its headed... It stops the boat and takes ages to get going again.
Plus, as you mention, once the full change has occured you will be on a reach instead of close hauled and heavy boats love a reach compared to a work!

Its certainly a great question so a report back next week would be good.

[Seasick Steve]

Seems to me just a question of applying two well-known principles:

• stay close to the rhumb line
• head towards an anticipated wind shift

N'est c'pas?

[GILow]

Originally Posted by Seasick Steve

Seems to me just a question of applying two well-known principles:

• stay close to the rhumb line
• head towards an anticipated wind shift

OK. Happy with the first point, makes sense.

The second point, I am not questioning the validity of your statement, just curious to know where you have heard this stated. Seems to encapsulate my problem pretty well, and I wonder if my lack of formal sailing training means I missed this one somewhere.

Matt

[Stumble]

How likely is it that if you start on port you will be lifted to the mark? The ideal solution is starting on starboard and tacking right where needed to be lifted to the line on port. Minimum distance sailed, all at the prefered AWA. However this is incredibly difficult to call 30 miles out, so you have two real options....

1) Sail additional distance on starboard early and just over stand the mark a little. This minimizes tacking which on a big cruiser is a good thing.

2) start on port and hope to get lifted. And short tack if you don't.

I would go with 1. 2 means all your starboard sailing is on an unfavored knock, and you could require more tacks to reach the destination. Unless I was very confident about the magnitude of the incoming knock and felt the odds on making the mark on one tack were very high.

[GILow]

Originally Posted by MarkJ

Its certainly a great question so a report back next week would be good.

Ha ha. Darn full time cruisers! You actually assume I will get a chance to go sailing sometime soon.

But I will try to report back within the next 6 months.

Matt

[Seasick Steve]

I think I first read it in Tom Cunliffe's The Complete Yachtmaster, possibly the most brilliant skippers' guide ever. Makes sense: If the wind is likely to come from, say, further south later on you want to get to what will be windward before it starts getting difficult.
But I'm a bit of a tyro at this really - I've done most of my sailing in fairly sheltered coastal and inshore waters where strategy is less important than on a long offshore passage. So you might not want to take my word for it