Anatomy of A Boat Wave
There is a definite science to creating a perfect boat wave. But for the most part a wave is a wave and nature creates great waves all the time. As wakesurfer, all we are really trying to do is mimic the variables that converge to create ocean waves. All of the newest boats on the market sport some very fancy equipment all designed to create a perfect wave, but this type of technology isn't exactly accessible to all.
Still, we all want to get the best wave we can out of our old faithful vessels.
There comes a point where you have to put aside all of the hyped up surf systems and fancy ballast tanks, and take things back to basics. Those things can certainly help your wave, but what I have discovered is that once you understand how a wave is formed by a boat then you can easily dial in the shape and speed. Ultimately this is done by fine tuning the weight and displacement of your boat, but before you start finessing your boat weight, let's consider the parts of a boat wave one by one.
The Trough
When you look at a wave face on from a boat you can see that it has a very distinct curvature at the bottom. This bottom area of the wave valley is called the trough. The trough is the lowest point of the wave and is the source where the thrust of the wave is created. You can visually measure the trough of the wave by looking at the depth of it from the swim platform. The deeper the trough, the higher your wave will be.
A deeper trough will also generate more usable thrust across the face of the wave.
The Wave Face
The face of the wave is your riding surface. The face of the wave is what receives the most impact as you change and finesse the minor variables of your boat. If the face of your wave is elongated and short you will have a slow and mellow ride. However, if the wave face is tall and relatively compact your wave will generate a lot of thrust, but less surface area for riding. Generally, riders want to find a balance between usable wave area and moderate speed. For most boats, a wave that measures a little above waist high and has a slight elongation is usually best.
The Crest
The crest is of course the highest part of the wave. Usually you can tell everything you need to know about your wave by looking at the crest. A healthy looking crest will have a slight amount of white water but not enough to crowd out your wave face. A crest of white water only forms on a breaking wave. An ideal wave for surfing will always be right at the point of cresting, and if you find that your crest is curling or creating a mini barrel then you’re golden.
Variables that Affect Boat Waves
Fetch/Wind - The wind, or fetch as it is more properly called in science, is often an overlooked factor when it comes to wakesurfing. However it can adversely affect your ride. It is important to consider which direction the wind is blowing and align your wave accordingly. A head wind is never a good thing for wakesurfing. This will always cause your wave to fragment. The best practice when it comes to wind is to place the wind behind the rider and match the angle of the wave the best you can.
Propellor - The prop of the boat will automatically throw water in one direction or the other. Most boats will come with a prop that spins clockwise and will thus throw the water in the direction of the port side of the boat. In any case, it will be abundantly clear which side of the boat the prop spins toward and typically that is the side of the wave you want to work with.
Boat Displacement - The single biggest factor of generating great boat waves for wakesurfing, though, is the displacement of the boat. Weighing down the back of the boat only will create a shorter steeper wave. Evenly weighting the boat will cause the wave to elongate and create a shallow, but long riding surface. Finally, weighing one side of the boat more than the other will cause the wave height to increase as more water is being displaced into the shape of the wave. Ultimately, the more water you displace, the more usable water you have to mold into the perfect wave. So when it comes to making great waves, weigh down the boat first and all other factors will follow suit.
Still, we all want to get the best wave we can out of our old faithful vessels.
There comes a point where you have to put aside all of the hyped up surf systems and fancy ballast tanks, and take things back to basics. Those things can certainly help your wave, but what I have discovered is that once you understand how a wave is formed by a boat then you can easily dial in the shape and speed. Ultimately this is done by fine tuning the weight and displacement of your boat, but before you start finessing your boat weight, let's consider the parts of a boat wave one by one.
The Trough
When you look at a wave face on from a boat you can see that it has a very distinct curvature at the bottom. This bottom area of the wave valley is called the trough. The trough is the lowest point of the wave and is the source where the thrust of the wave is created. You can visually measure the trough of the wave by looking at the depth of it from the swim platform. The deeper the trough, the higher your wave will be.
A deeper trough will also generate more usable thrust across the face of the wave.
The Wave Face
The face of the wave is your riding surface. The face of the wave is what receives the most impact as you change and finesse the minor variables of your boat. If the face of your wave is elongated and short you will have a slow and mellow ride. However, if the wave face is tall and relatively compact your wave will generate a lot of thrust, but less surface area for riding. Generally, riders want to find a balance between usable wave area and moderate speed. For most boats, a wave that measures a little above waist high and has a slight elongation is usually best.
The Crest
The crest is of course the highest part of the wave. Usually you can tell everything you need to know about your wave by looking at the crest. A healthy looking crest will have a slight amount of white water but not enough to crowd out your wave face. A crest of white water only forms on a breaking wave. An ideal wave for surfing will always be right at the point of cresting, and if you find that your crest is curling or creating a mini barrel then you’re golden.
Variables that Affect Boat Waves
Fetch/Wind - The wind, or fetch as it is more properly called in science, is often an overlooked factor when it comes to wakesurfing. However it can adversely affect your ride. It is important to consider which direction the wind is blowing and align your wave accordingly. A head wind is never a good thing for wakesurfing. This will always cause your wave to fragment. The best practice when it comes to wind is to place the wind behind the rider and match the angle of the wave the best you can.
Propellor - The prop of the boat will automatically throw water in one direction or the other. Most boats will come with a prop that spins clockwise and will thus throw the water in the direction of the port side of the boat. In any case, it will be abundantly clear which side of the boat the prop spins toward and typically that is the side of the wave you want to work with.
Boat Displacement - The single biggest factor of generating great boat waves for wakesurfing, though, is the displacement of the boat. Weighing down the back of the boat only will create a shorter steeper wave. Evenly weighting the boat will cause the wave to elongate and create a shallow, but long riding surface. Finally, weighing one side of the boat more than the other will cause the wave height to increase as more water is being displaced into the shape of the wave. Ultimately, the more water you displace, the more usable water you have to mold into the perfect wave. So when it comes to making great waves, weigh down the boat first and all other factors will follow suit.
