How to Win

Ruling the waves

Sailing fast in big waves is the most exhilarating facet of being a oat. Jon Emmett coaches you through the troughs and crests at top speed

Have you ever stood in the sea and felt the action of the waves on your legs? e surge as the waves push you forward towards the beach and then the sucking action pulling you back out to sea. at is correct: the waves don’t simply ‘go one way’ and the way we steer in waves can have a huge e ect on our Velocity Made Good (VMG). is is why we o en see bigger speed di erences in wavy conditions than in at water racing.

You have probably noticed the

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Blasting down waves is one of the greatest thrills in sailing

wave e ect many times before, especially when you are trying to hold a boat by the beach when launching or waiting for your trolley WATER FLOW IN A WAVE to recover your boat, but have you BELOW Water fl ow in a wave really thought about the current between waves which at one point is pushing and another point pulling?

Fig 1

HEIGHT HEIGHT HIGH WATER HIGH WATER

ACTUALLY ACTUALLY CHANGES CHANGES CURRENT CURRENT HERE HERE

CURRENT CURRENT

WIND WITH AND AGAINST CURRENT WIND WITH AND AGAINST CURRENT WIND WIND

CURRENT CURRENT

MAXIMUM FLOW MAXIMUM FLOW OF WATER OF WATER

On a local scale we know that water always likes to run downhill. You can see this on the waves; the water is running from the top to the bottom which means the ow of the water can be considered from the peak to the trough. A quick note when we draw diagrams of waves like this: they can o en look like tide charts. However, for tide charts it is not that simple with the ow of water rarely changing at exactly high and low water but that is a topic for another article! e reason we mention current, as in the underlying current is that it is relevant to wave height and length. So, when the wind is with the current it really attens the waves. A good example is Portland harbour in a North Westerly wind at spring tides owing out of the harbour. e water can be super at even though it is over 20 knots. However, if the wind were South Easterly then the harbour would de nitely not be at, you would have very choppy water inside the break water and the waves by the harbour entrance would best be described as trying to sail in a washing machine. Where the current ow is at its strongest is just outside the entrance having been squeezed through the gap. Imagine turning a bottle of water upside down, the strongest ow is just a er the bottle opening – not exactly at the narrowest point. “Outside” in Weymouth Bay can get very large waves in a South Easterly

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e interaction between wind and current and depth all have a profound e ect on the shape of waves

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e di ernce between real waves and how they are drawn in a text book is signi cant

WAVES ON SHALLOW WATER

Fig 3

OCEAN SWELL VERY DEEP WATER OCEAN SWELL VERY DEEP WATER

Another factor is water depth, something I think that most of us intrinsically know but rarely think about. So, when trying to choose similar venues to train in this is an important decision. You get huge ocean swell coming in from the west of the Canary Islands where the water is hundreds of metres deep. You would never expect to get that same swell on a shallow inland water, however large the area of water! e second point is that waves are not uniform in size and direction. Something that anyone who has been hit by their own personal wave o the start line which no one else seemed to get can relate to and it is much the same way that you are looking for that perfect high speed at spot to execute the perfect gybe (or tack). e more you get your head out of the boat the more likely you are to see the best place (usually a ‘ at spot’).

In the extremes we have waves which are going straight on and waves with are going side on. Although normally it will be somewhere in between. A good analogy is the reach and the approach to rig set up. With a really tight reach (almost beating) we have a very similar rig set up to upwind and with a very broad reach (almost a run) we have a very similar rig set up to downwind and then there are many shades of grey in the middle where even small di erences in tuning makes a di erence in boat speed which will be noticeable over a long leg. is is also true when it comes to steering for the waves.

WIND

Fig 4

TEXT BOOK WAVES FROM ABOVE

REALWAVES FROM ABOVE

TEXT BOOK WAVES FROM SIDE

REALWAVES FROM SIDE

TEXT BOOK TIDE TIMES

REAL TIDE TIMES

e side on wave

Here the main issue is being ‘picked up by the wave’ and carried to leeward which, due to the wave being side on, is almost directly downwind. You may have seen spectacular wipe outs when boats are hit side on by a huge wave.

A secondary issue is the power will tend to go very on and o whether you are at the top of the wave or the bottom of the wave, being pushed or pulled. So precise steering becomes very important. e key idea here is that you need to maximise your time on the windward side of the wave (where it helps you) and minimise your time

on the leeward side of the wave where it is pushing you downwind. is requires a big steering moment, maybe an even bigger ‘stab’ at the precise moment.

e front on wave

If side on waves is all about precise steering, then front on waves is all about controlling the power. Every wave is literally trying to push you back, so in most conditions you need to take as much power as possible to climb over them. is means when going down the wave you bear away as hard as you can (whilst maintaining maximum VMG) to not only maximise your time on the “good side of the wave” but to build as much speed as possible to help you steer up and over the “bad” side of the wave”. Here the steering is smooth and very o en footing works very well (sailing as low and as fast as you can with maximum VMG).

It is worth making a note here that in fast boats, usually those which plane upwind you do need to be careful that you don’t launch o the top of one wave and then end up burying the bow into the next wave. In non-planing boats it is all about perfectly timed forward and backwards movements by the crew to keep the boat pitch as stable as possible (imagine you are trying to keep the boat as close to horizonal at all times). For foiling boats, the ride height needs to be set so that you are as close to the water as possible but with the hull never making contact with the waves… easier said than done!

Kinetics

No doubt you have seen the huge work rate of the Olympic sailors. is is not just hard work physically, but also the technique is so important. If you do a big forward movement and bury the bow when you should have moved backwards then it is far worse than doing nothing at all. e more waves you pass the more frequently you need to move your body. For slower boats this means most of the body movements are upwind because the waves are coming towards you whereas downwind the waves are going away from you but as soon as onto the tiller extension and lean back and out away from the mainsheet ratchet block. Likewise, to bear away we need to ease the sheet (just like we would for rudderless sailing) to keep the boat at and as we move forward (to keep the bow in the water going down the wave) we are naturally pulling the tiller extension towards us.

Timing is of course key. e boat does not turn “at the front” like the wheels of the car when you turn the steering wheel (especially in a van with the wheels right at the front of the vehicle) but rather around the trailing edge of the centreboard. is is why raking the centreboard forward and a is so key for good performance and to a lesser extent why the position of crew weight also a ects steering. So, in your head the steering action is being performed with the bow in mind (get the bowdown at the top of the wave) but remembering the turning comes from approximately the centre of the boat!

SIDE ON WAVES

WAVE HELPS WAVE PUSHES SIDEWAYS

FROM THE SIDE

TROUGH

PEAK

TROUGH

FROM ABOVE

Fig 5

QUICK LUFF FRONT ON WAVES

MINIMISE TIME UPHILL

FROM THE SIDE

TROUGH

PEAK

TROUGH

FROM ABOVE MAXIMISE TIME DOWNHILL

Fig 6

BEAR AWAY DOWN THE WAVES

HEAD UP GOING UP THE WAVES

you start to surf / overtake the waves you need to do the same forward and backward actions downwind.

Moving the weight backwards in the boat makes it easier to bear away, therefore we put our weight back at the windward mark. Whilst having the weight forward and the bow digging in with a slight amount of leeward heel makes it easier for the boat to head up, which is why this is how we start a tack, but it is not that simple.

In practice especially in single handed boats it tends to work very well to head up the wave you steer up, weight back (so as not to bury the bow) and sheet in. All three would be achieved if you just hold

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ABOVE RIGHT AND BELOW

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KINETICS

BOAT WITH WAVES BOAT WITH WAVES FROM IN FRONT FROM IN FRONT WEIGHT FORWARD TO WEIGHT FORWARD TO TO GET BOW DOWN TO GET BOW DOWN

WEIGHT BACK TO BACK TO GET BOW UP GET BOW UP

Fig 7

Conclusion

One of the great joys of sailing is every day is di erent. To sail fast in a venue not only do we need to learn about the winds and the currents but perhaps most importantly how to sail fast in the waves.