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Video 5.2.1 The North Atlantic: from Gibraltar to the Equator

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Strategies for winning. Meteorology in a round the world regatta

Барселонский университет

4.5 (оценок: 46) | Зарегистрировано учащихся: 1.8K

In this course you can learn about the mechanics of global weather, the foundations of ocean meteorology, predictive modeling and how sailors receive data via satellite and use high-performance navigation software. This course looks at oceanic meteorology and climatology through the lens of the sport of sailing. You will gain a basic knowledge of meteorology needed by sailors to take part in a regatta such as the Barcelona World Race, the only double-handed, round the world regatta with no stops. You will learn about the strategies employed during a round the world regatta and how these are put to use on board the latest ocean racing yachts.

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Из урока

Climatology and meteorology in the Barcelona World Race: From the Mediterranean Sea to the Indian Ocean

We begin now by going over the Barcelona World Race round the world route. In Module 5 you will learn about general and specific strategies for sailing from Barcelona to the Indian Ocean.

Video 5.2 The Atlantic: From North to South. General strategy0:54

Video 5.2.1 The North Atlantic: from Gibraltar to the Equator18:29

Video 5.2.2 The South Atlantic: From the Equator to the Indian Ocean13:20

Преподаватели

Tomàs Molina

Текст видео

[MUSIC]

North Atlantic First.

Once we get out of Gibraltar we have to think about where we're going to cross

the Equator and that would determine our strategy in the North Atlantic.

We can see the Equator here, we know the doldrums,

the wind is more or less...

Here.

And we also know from experience because we've done our homework

before that the best crossing area is where, on average,

this windless area is the narrowest which is about here between 28 and 30.

This is where you have the best chance to get through this windless area quickly.

We also that over here roughly,

we have the high pressure of the Azores and eventually,

we have to deal with the high pressure of Santa Helena for the south.

Let's go back to North Atlantic.

So in the North Atlantic, we get out of Gibraltar, we want to go over there.

How do we get there?

Seems simple.

We can just go the shortest route.

Not quite.

We know that the wind around this system move more or less like this.

And that means that here the winds go more and more right.

They are more and more at it.

If you do a route, I will pick up another color to show you.

Okay in blue if we think about a really short route,

a really short route would be like this for instance.

Seems good, good, this is the shortest route.

Which you can already see here, that it gets more and

more right to wind, here it's difficult.

You have to jive downwind to slow, and

once you are over here there are no options left.

The wind is to the right, you can only go downwind with the wind,

you cannot go further over here.

I'll show you another example with some routing, all right?

So basically what you want to do here is you want to go as far west as you can.

Without getting into the high pressure of the Azores, because there is no

wind there, and then a really quick angle down here, and come in like this.

Now, here, you can still choose where you want to cross this,

because this is only a statistical average.

Which we know from climatology, from this is more or

less the best area to cross the Equator.

We want to go here.

So anyone that manages to cross a little bit further East

is ahead in the way to the finish.

Distance to the finish.

On this Atlantic route,

down there's always the trade off between trying to point towards the mark.

The mark is over here.

That's our entry to the Southern Ocean and trying to deal with the weather and

try to find the quickest way across the weather.

And that is always, the conflict, the sailor,

the strategist, the navigator, has on board, what do I do?

Do I go for the medium term, long term, or do I go for the immediate gain?

Over here, it's really easy to be the first on the leader board.

If you want to be the first on the leader board, just point towards Capetown,

very easy.

You'll be first after one or

two [INAUDIBLE], after 12 hours, you'll be first, right?

You'll be first only at that time.

Later on you will pay dearly, as you cannot get back here.

We've already explained to you that you have to deal with the Azores high and

you have an entry point into the doldrums.

At this moment, this is the last race, Barcelona World Race 2010.

The Azores high is pretty far south.

It's over here not very strong.

You can see there's a bigger low pressure with south-westerly north-westerly

winds pushing here.

Here you see the first boats coming out of the straight of Gibraltar.

Let me put on the animation and you will see how they dealt with it last time.

Then you can see the first boats coming out.

They start sailing towards

the west here trying to get towards those winds here and eventually

finding these northwesterly winds behind it and then to get under the Azores high.

Here you see the shifts going to the west.

First boats have and now it gets interesting because

here we can see that the boats have managed to gain quite far in the west, and

that will always pay off in the end, once you start approaching the Equator.

However, if you gain early in the west, you have to deal with the Canary Islands.

The Canary Islands, a nice place to go to, but are very high.

They are very high and they create an enormous wake in their lead.

Normally the winds are from North East here,

the lead is on the other side of the Islands.

It is wind that's showing behind the wall basically,

I'll show you a picture just so you can have a look at that.

So here I'll show you a picture of the Canary Islands,

you can see Gran Canaria over there.

Tenerife, over there.

Tenerife and Gran Canaria are the most important islands.

And you can see that the effect of these islands goes very, very far down.

Up to a thousand kilometers,

you can still traces in the clouds of the effect of the Canary Islands.

Having two massive walls here on the ocean in

the flow of the wind will give big effect downwind.

So the lee of the islands is over here.

And over there.

The boats going down towards the Equator, north Atlantic,

have to deal with the Canary Islands.

You go through them.

You got accelerations in between the islands but

there's no wind behind the island.

How do we stay in that area?

Or you go in between the African coast and the Canary Islands.

But then you are committed long term.

You are very close to Africa.

How do you ever get back west again?

At some states you're going to have to sail through the wake

of the Canary Islands.

Or, do we go out west early, forget about the Canary Islands, and

try to start to come down here.

That's a very important choice once you get out of Gibraltar,

what to do with the Canary Islands.

They're always in the way.

Okay, now we've seen what the problem can be for

the Canary Islands, we can also see what the boats did in the last edition.

Some of the boats made significant gain to the west.

They seem to have the plan to go west of the Canary Islands and

not get stuck behind the Canary Islands.

As you can see here on the map where I said before, once you get stuck in between

the African coast and the Canary Islands, you're in trouble.

It's very hard to get back out west again.

All right so anything you can gain in the West earlier on

is common knowledge amongst navigators.

This capital later on would be big gain later on.

Here you can see that the low now has started to move through,

you can see the Azores high over here starting to reform.

It will probably shift up North a little bit and very careful.

It shouldn't shift east.

Because if it shifts east towards the Canary Islands,

the boats that went furthest west, maybe they get caught by the Azores high, right?

Lighter winds.

Let's have a look how it thins out here.

Okay, very nice picture here.

You can see the Azores high here.

There's just wind on the eastern side of it so

it looks like this boat's going about perfect.

They're not in the Azores high, they're not in the lee of the Canary Islands.

Great. These boats further back,

you can see that they've started to point towards the mark.

The mark is down here somewhere, right?

The entry into the southern ocean close to South Africa.

That's great short term.

You gain on the rankings, the famous sketch we spoke about.

You can already see here they are creating problems for themselves.

They will have to deal with the Canary Islands.

Some of them are even aiming at the gap between Africa and

the Canary Islands, which is an even bigger problem.

And these boats, they've done it perfectly.

Not in the Azores high, not in lee of the islands.

They will probably go down here, come back out maybe once more, and

then go straight to the Equator for

the entry point into the doldrums where they think it's going to be best.

So here a little bit further now,

we can see that the first boats here have changed.

This boat here is almost sort of on direct routes towards where we want to go over

here roughly, 28-30.

You can see that these boats are in a world of trouble now.

They got the Canary Islands in front of them.

This boat is going to go in between the gap in this case Fuerteventura and

Gran Canaria for to drive out once more.

And then get stuck here because if you sort of go west straight off of

Gran Canaria, there's no wind behind Gran Canaria.

These boats have decided in the last moments to avoid the Canary Islands and

they're coming, I mean, course is down here, we're doing towards South Africa.

Boats are sailing away, almost, from South Africa.

These boats have done right, let's have a look how it goes further.

You can see the Azores high now very well defined over here,

winds go around this way around the high and you can see that these first boats

here are in the northeasterly trade winds, all right.

North easterly trade winds start about here roughly.

A little bit over here as well.

The main batch of north easterly trade winds is all the way here and

then the Azores high in between the Azores high and the doldrums.

Going forward, stop once more.

And we can see how it finishes with our friends back here.

As you can see they've got all sorts of issues to deal with because of

the Canary Islands jiving back and forth here.

All not very good.

These boats have made it simple, went out west, down, west,

close to the Azores high, find the corner, do not go too far because you get

into the light of the Azores high and then just go down into trade winds.

These boats are gone.

Those boats will never ever see them again.

From here on to the Equator, it's sailing as it's supposed to be,

as they call champagne sailing.

Nice winds, trade winds, 15 to 20 knots, sometimes a few showers,

maybe 25 knots in a shower, in a squall, you know.

The only intense part here is to deal with squalls.

Another subject we've spoken about the squalls.

Squalls that suck the air, and squalls that rain when the air comes out.

And those are about the only things that you have to deal with.

There's not a lot here left to do.

You can only go straight line.

You can see here, this boat would jibe here and now,

you'll be sailing away from where you want to go.

So no one really wants to do that.

Basically you're on rails here.

In that you know you can't go anywhere else.

Where ever you jibed here decides where you end up at the Equator.

Very important.

These boats, they're stuck here at the African coast.

They either come out now, they'll be sailing roughly like that.

Or they try to postpone, they postpone, they postpone their pain basically.

And do it later on, will be even worse,

because here there're also the Cape Verde Islands.

And again, big islands,

big volcanic islands, creating a lee, creating problems.

You want to stay away from islands if you can.

Let's go forward.

We're now a little bit further down the track.

These boats have just done about perfect, well to the west of the Canary Islands, as

a result they also stayed west of the Cape Verde Islands, which was mentioned before.

They're big islands as well, creating a lee.

This boat has paid dearly to get out west over here but

as you see has done better than these boats because these boats are just about

starting to take their medicine now and tried to get out west.

This boat is discovering Cape Verde islands in front of him,

doesn't have a solution yet.

Let's go forward and have a look how it goes.

Go a little bit quicker.

Interesting the little jibe here of the green boat.

Didn't go far enough in the beginning in order to jibe out.

Now to jibe out to get west of the Cape Verde Islands.

And again, it's still quite close because you can see where the wind is coming from,

all right?

And you saw from the satellite picture before that this lee,

this effect of this island goes very far downwind.

So he'll have a few difficult hours here sailing through the lee

of the first Cape Verde Island here.

This one has decided to go East of it, I don't know where he's going to go west but

you can already see the doldrums over here, right?

No wind anywhere here, no wind, no wind, no wind, no wind here.

You can see that it's roughly the narrowest at the moment,

at around 34, maybe?

I mean 35 is better, but it's even further away from where we want to go.

We want to go to South Africa.

So we're trying to find the compromise here between the shortest route and

the quickest route and it seems to be at about 33 to 34 at this moment.

Again this will change, but

these boats can no longer change, these boats cannot change how far west they go.

These boats can always go a little bit east if they need to.

Right? You can see where the wind is coming from.

They're sailing downwind.

For these boats if they've gone a little bit too far west they can always

come a little bit more closer to the wind which is faster.

And cross a little bit further east.

That's only coming up a little bit, going faster.

These boats to go through the west have to jibe.

And you can see here from the jibe that their basically

sailing away from South Africa.

Let's go forward again.

You can see the leading boat, the blue boat here,

has started to slow down in the doldrums.

Right, you can see the southeasterly trade winds that we will talk about in

the next subject already here just south of the Equator.

And here you can see the windless area in between the two.

This windless area is known to not be very active when described on GRIB files.

This is a GRIB file, what you're looking at.

Satellite pictures are more accurate.

It gives you an indication.

You can see that here, you know the transition between the south

easterly trade winds and the north easterly trade winds is easier.

The winds here are further northeast, here they're further southeast, and

they oppose themselves, creating huge clouds, huge clouds that circle the winds.

Here the winds are further east northeast,

at east southeast they sort of merge more into each other.

All right, it's making the confrontation, the convergence line between the two

different systems, not as marked and therefore easier to get through.

So this boat is, I would say, on the edge.

It would be interesting to see this pink boat gains anything.

The pink boat it a little bit further West.

Maybe they can gain something.

You can see that these boats are trying to move with the Cape Verde Islands after

having dealt with the Canary Islands and

this boat is going the shortest route hoping for some miracle to happen.

Okay.

A little bit further now we can see here that the chasing pack has gotten closer,

in sailing we call that compression as the fleet gets closer together.

And that is basically because the first boat ran into lighter air.

The good thing about the doldrums is that we know the first boat out

will then be gone.

So normally, what you're trying to do here is that if here you had a lead of let's

say 50 miles you come out and you can stretch it back to 50 miles.

Maybe it's somewhere in the doldrums so

it's only five miles, but it should be first in, first out.

But there is a bit of luck involved.

Sometimes you can have one unlucky cloud and all of a sudden you're first in and

last out, so this is one of the most nerve-racking times for

any sailor that does the North Atlantic basically.

Any around the world sailor, going through the doldrums

is a nerve-racking time because you're not certain about the outcome of it.

Everything else,

you can more or less deal with it, here it depends on the individual cloud.

And as you're going very slowly, you can hardly react.

You cannot say there's a cloud coming there,

let's go over here to try to avoid it.

You have to got through it.

Go down straight south.

Try to get out of this area as quick as possible.

Let's go further down.

Okay.

You can see the blue boats out of it now.

I would say, the pink boat has made some gains,

not relative to where they're going, South Africa, or south of South Africa.

But you can see, that as far as north, south concerned, they're almost equal now.

Here to my eye, the pink boat has made some gains on the blue boat.

The blue boat has been the furthest east trying to defend that position against

the chasing pack here, trying to find the right compromise between the shortest

course, which is over there somewhere and the quickest course and

the pink boat has attacked by the westerly side trying to get to an area of

the doldrums that is maybe easier to get through.

But again, the doldrums you need some luck there.

It can all depend on the individual clouds.

Here you can see the menacing pack behind.

Got closer but now the distance is increasing again

as these boats are now in the southeasterly trade winds.

These boats haven't come out of the doldrums yet.

And these boats haven't even entered yet.

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