Why River Sailing Is Different From Sailing on Open Water

On a river, the wind you see at the masthead may not be the wind reaching your sails.

Sailing is sailing. The basic principles do not suddenly change because you leave the sea and enter a river.

The sails still generate aerodynamic force. The keel or centreboard still resists sideways movement. The rudder still steers the boat. You still tack through the wind and gybe with it behind you.

But put the same boat on a relatively narrow, tree-lined river and sailing can become a remarkably different game.

Trees interfere with the wind. Banks create shelter. Buildings generate turbulence. Bends change the apparent orientation of the course. The current may help you in one direction and hinder you in another. The available water limits your tactical choices.

And sometimes you can look at the burgee at the top of the mast, see it streaming confidently in one direction, while the sails appear to be experiencing something quite different.

Welcome to river sailing.

For some sailors these complications sound frustrating.

I think they are part of what makes river sailing so fascinating.

The Wind Doesn't Simply Blow Across a River

When we first learn to sail, diagrams generally show beautifully behaved wind.

There is an arrow labelled WIND.

The arrow points in one direction.

We then learn where to position the sails relative to it.

Real wind is considerably less cooperative, particularly on an inland river.

Imagine a breeze approaching a river surrounded by mature trees.

The air cannot simply travel through the trees unaffected. It has to flow around and over them. Individual trees, hedges, buildings and changes in terrain disturb that flow.

The result can be a complicated mixture of:

• relatively clean wind;

• sheltered areas;

• gusts;

• turbulence;

• wind shear;

• eddies;

• headers;

• lifts;

• and occasionally patches that seem to contain almost no useful wind whatsoever.

Two boats separated by surprisingly little distance can therefore experience different conditions.

That makes observation enormously important.

The Masthead Can Tell Only Part of the Story

This produces one of the fascinating features of river sailing.

Look upwards and your burgee may indicate one wind direction.

Look at the jib tell-tales and they may suggest something slightly different.

Look at the water fifty metres ahead and yet another story may be developing.

That isn't necessarily because one of your indicators is wrong.

The wind can genuinely be different at different heights.

Close to the surface, friction with trees, banks and the ground slows and disturbs the airflow. Higher up, the wind may be stronger and less affected by some of these obstructions.

A tall mast can therefore extend through several slightly different layers of moving air.

On an open stretch of water the difference may be relatively small.

Beside a wooded riverbank it can become much more noticeable.

This is why I regard the burgee as one instrument rather than the instrument.

I also want to see the sails, tell-tales, water, nearby boats and trees.

Together they tell me much more.

Trees Create Both Shelter and Turbulence

Trees are particularly interesting.

Sail close to a heavily wooded bank with the wind coming from behind those trees and you may enter their wind shadow.

The wind can weaken dramatically.

But the effect isn't simply an area of reduced wind immediately behind the trees.

Air flowing across an obstruction can become turbulent downstream.

Think about water flowing past a rock in a stream.

Behind the rock there isn't simply stationary water. There are swirls, eddies and constantly changing flow.

Air can behave similarly.

A line of trees can therefore create a region in which the wind continually changes strength and direction.

One moment the boat is powered.

Seconds later the sails soften.

Then a gust arrives from a slightly unexpected direction.

This is why river sailing rewards sailors who continually adjust rather than set the sails once and leave them alone.

Buildings Can Be Even More Interesting

Buildings can produce surprisingly dramatic effects.

Air flowing around a clubhouse, house, boathouse or industrial building can accelerate around corners, separate from surfaces and produce turbulent wakes.

You can occasionally sail towards what appears to be a sheltered area and suddenly receive a strong gust.

The opposite can happen just as quickly.

This becomes particularly interesting when racing.

A sailor who has sailed the same river for years may know that a particular group of trees usually produces a lull, or that a certain gap between buildings sometimes funnels the wind.

That local knowledge can be extremely valuable.

But it should never replace observation.

Today's wind direction may be only ten degrees different from yesterday's.

That can completely alter which obstacles matter.

River Bends Change the Game

On open water, the relationship between the course and the wind can remain relatively straightforward.

A river bends.

Suppose you are sailing upstream towards a mark.

For one section, the river may run almost directly into the wind.

Round the next bend, the same wind might suddenly put you on a reach.

Another bend might require another tack.

The wind hasn't necessarily changed.

The orientation of the sailing area has.

That means river sailors continually reassess their situation.

Instead of asking only:

"Where is the wind coming from?"

we also need to ask:

"What does that wind mean for the next section of river?"

This makes bends tactically fascinating.

Then There Is the Current

Wind moves the boat through the water.

The river moves the water across the ground.

Those are different things.

Suppose your boat is sailing through the water at 4 knots while the river current is flowing downstream at 1 knot.

Very approximately, if you are sailing directly upstream your speed over the ground could be:

4 - 1 = 3 knots

Sail directly downstream and it could become:

4 + 1 = 5 knots

Real sailing is rarely quite that simple because the boat and current may be travelling at different angles, but the principle matters.

And the current isn't necessarily identical across the whole river.

It may be stronger in the deeper central channel and weaker near the bank.

Suddenly the shortest route may not be the fastest route.

The Bank Can Become Part of Your Tactics

Suppose you are racing upstream against the current.

You might choose to sail closer to the bank where the current is weaker.

But now another problem appears.

The bank might also shelter you from the wind.

So which is better?

Stronger wind and stronger adverse current?

Or weaker current and weaker wind?

There isn't a universal answer.

That is precisely what makes the decision interesting.

The correct choice may change within minutes.

River sailing becomes a continuous optimisation problem.

You are balancing wind strength, wind direction, current, distance, traffic and available space.

You Cannot Always Tack When You Want To

On open water, a tactical discussion might conclude:

"We should tack now."

On a river the answer may be:

"We should—but we can't."

There might be another boat alongside you.

The bank may be approaching.

A moored boat may restrict the available water.

A navigation channel may need to remain clear.

A bend may make the manoeuvre undesirable.

Or the next tack may leave you trapped beneath trees with almost no wind.

This is one reason why deciding when to tack becomes such an important river-sailing skill.

The theoretical best tack is not necessarily the practical one.

Sometimes you have to think two or three manoeuvres ahead.

The Riverbank Is Not Always Your Friend

There is a great temptation to use every centimetre of available water when racing.

Sometimes that is exactly what you should do.

But there is a danger.

Sail too close to a bank and several things can happen simultaneously.

The wind may become weaker.

The wind may become more turbulent.

Your tactical options disappear.

And if something unexpected happens, there may be very little room to recover.

That last point matters.

A few metres of extra water can sometimes be worth more than gaining another metre towards the bank.

Read the Water

This connects directly with one of my favourite sailing lessons:

Stop staring at the sails and start looking outside the boat.

On a river, the water ahead can reveal a great deal.

A darker patch may indicate stronger wind.

A line of ripples may show an approaching gust.

A smooth patch may indicate lighter pressure.

Other boats provide information too.

If a boat fifty metres ahead suddenly heels, something has happened.

If three boats ahead simultaneously slow down, that is useful information.

If boats on one side of the river are moving noticeably faster than boats on the other, ask why.

They are effectively sailing weather stations.

Watch the Trees as Well

Trees aren't merely obstacles to the wind.

They are also indicators of it.

Look at the upper branches.

Are they moving?

Which direction are the leaves being blown?

Is one group of trees moving while another remains still?

This can sometimes reveal an approaching gust before it reaches the water around you.

River sailing encourages you to develop an increasingly large field of attention.

The beginner looks at the sail.

The improving sailor looks at the boat.

The experienced sailor is increasingly looking at the environment in which the boat is about to sail.

Headers and Lifts Become Particularly Important

A river's disturbed wind makes small changes in direction extremely significant.

Imagine sailing close-hauled when the wind shifts.

If it moves towards the bow, you are headed.

If it moves aft, you are lifted.

On open water you might have time to observe a developing wind shift and decide what to do.

On a river the consequences can arrive remarkably quickly.

A lift might allow you to continue towards the next bend without tacking.

A header might suddenly make the opposite tack much more attractive.

But because the river is narrow, you may have only seconds to exploit it.

This is where sailing moves beyond simply knowing the controls.

You begin making decisions.

Sometimes the "Wrong" Side Works

One of the delights of river racing is watching apparently strange decisions succeed.

Someone sails towards what appears to be the wrong bank.

Why?

Perhaps they have spotted stronger pressure.

Perhaps they know the current is weaker there.

Perhaps they expect a lift.

Perhaps the next bend favours that position.

Or perhaps they have simply made a mistake.

You won't know until the situation develops.

That uncertainty makes river racing particularly interesting.

Champagne Makes These Effects Especially Noticeable

Sailing Champagne, our A-Rater, makes me particularly conscious of the river environment.

A longer boat carrying a substantial sail area can respond dramatically to changes in pressure.

A gust arriving can suddenly transform the boat.

Then the wind disappears behind trees and everything changes again.

With several people aboard, the challenge is not merely recognising the change but coordinating the response.

The helm may need to alter course.

The mainsail may need adjusting.

The jib needs trimming.

Crew weight may need moving.

And ideally much of that happens before the boat has lost momentum.

That last point is particularly important.

Momentum Is Precious

In light, disturbed river winds, boat speed is something worth protecting.

If the wind briefly disappears, a boat that already has momentum can continue moving.

A boat that has been over-steered, over-sheeted or allowed to slow may stop.

Once stopped, restarting can be frustratingly difficult.

This is why smooth sailing matters.

Avoid unnecessary rudder movement.

Keep the sails working.

Anticipate changes.

Maintain flow.

Sometimes the best response to a short lull is surprisingly little.

Let the boat carry itself through it.

Local Knowledge Matters — But Observation Matters More

Experienced river sailors often appear to know mysterious secrets.

"Don't go under those trees."

"Stay on this side after the bend."

"There's usually more pressure near that bank."

Years of sailing the same stretch undoubtedly create valuable local knowledge.

But conditions never repeat perfectly.

Wind strength changes.

Wind direction changes.

Water levels change.

Trees grow.

Trees disappear.

Even seasonal foliage changes the airflow.

So I think the real lesson is not simply to memorise where the good wind normally lives.

Learn why it might be there.

Then look for evidence that it is actually there today.

River Sailing Is a Wonderful Classroom

Open-water sailing gives space.

River sailing gives problems.

And problems make us think.

Every few minutes the river asks another question.

Where is the next gust?

Which bank has the better wind?

Where is the current strongest?

Can I make that bend without another tack?

Should I tack now or wait?

Why has that boat suddenly accelerated?

Why have my tell-tales changed when the masthead burgee hasn't?

Can I maintain momentum through this lull?

There may not be a perfect answer.

You make your decision, sail another hundred metres and discover whether you were right.

Then you try again.

Why River Sailing Can Be So Much Fun

It would be easy to describe all this as making river sailing difficult.

I prefer to say it makes river sailing interesting.

A relatively short stretch of water can contain an extraordinary number of tactical and technical challenges.

You are not simply controlling a sailing boat.

You are interpreting a constantly changing environment.

Wind, water, trees, buildings, bends, banks, current and other boats are all providing information.

The more you sail, the more of that information you begin to notice.

And gradually something rather satisfying happens.

You stop merely reacting to what the boat is doing.

You begin anticipating what it is about to do.

That is one of the great steps in becoming a better sailor.

On a river, the wind you see at the masthead may not be the wind reaching your sails.

But once you learn to read the river, that complicated, imperfect and constantly changing wind becomes part of the fun.

And perhaps that is why river sailing can be so addictive.

Every trip along exactly the same stretch of water can present a completely different puzzle.

The river may be narrow, but the amount it can teach you about sailing is enormous.

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