Safety in kitesurf: kitesurfing rules

Punta Trettu Kitesurf

Kiteboarding row rules

In crowded conditions the possibility to collide with other kiters exists. It is important to know how to react in order to avoid accidents. The following are the most common right of way rules for kiteboarders.

Avoid collisions at all costs.

Follow the rules but not to the point of having a collision, even if you have right of way, you must act prudently to avoid an accident. Some sailors don’t know the rules. This is part of the “prudential rule”.

The Prudential Rule

There is no rule that excuses you, for not knowing the weather, having the correct gear, keeping a proper lookout, and avoiding accidents (Acting Prudently).

The incoming Kiter gives way to the outgoing kiter who is launching.

  • Situation: one kite is launching and ready to leave the beach, and another kiter wants to come in and land at the same time.Definition: The launching kiter is standing with their lines tensioned obviously ready to launch.
  • What to do: The incoming kiter should turn around and go back out for another tack, while the launching kiter gets off the beach.

The upwind kiteboarder gives way to the downwind kiteboarder.

  • Situation: when two kiters are on the same tack but their paths will cross. Usually the upwind kiter is not pointing as high as the downwind kiter.Definitions: the upwind kiter is sailing closer to the wind than the downwind kiter.
  • What to do: The downwind kiter has right of way, so they should continue to ride in the same direction and speed, the upwind kiter must give way, by altering direction or speed, usually slowing and going behind the other kiter.

The kiteboarder on port tack gives way to the kiteboarder on starboard tack.

  • Situation: When you meet another Kiter head on, and you are both on opposite tacks, the port tack rider gives way to the Starboard tack rider.
  • Definitions: When you have your kite on the right hand side of the wind window, between 12 and 3 oclock. you are riding on “Starboard tack” and have right of way. When you are riding with the kite between 9 o’clock and 12 o’clock. you are said to be on “Port Tack” you must give way.
  • How to give way: To give way to the Starboard tack rider, you should slow down or alter course (usually downwind keeping your kite low). The kiter of Starboard tack should maintain his direction and speed.

When crossing close to another kiter, the upwind kiter keeps his kite high, and the downwind kiter keeps his kite low.

  • Situation: You are riding on the opposite tack from another rider, you are close but but you will miss each other.
  • Definition: If it is obvious that you do not have to alter course or speed to miss the other rider, you should position your kite to keep it away from the other kite.
  • What to do: The kiter passing upwind raises their kite, and the downwind kite lowers their kite. Do not move your kite to the point where you will change speed or alter course significantly.

Do not jump when you are upwind of another kiter.

  • Situation: When you are preparing to jump, close to other kiters.Definition: If any part of your jump will take you over near to, or into the path of another kiter or their gear.
  • What to do: Keep a clear area ahead behind, and downwind of you before you jump. Keep in mind your jump may not go as planned, you go wipeout, or go higher and further than you planned. Also the other kiter could change course or act unexpectedly.

Look in all directions (including up) before you jump.

  • Keep a proper lookout at all times. Do not ride close to other riders, they could turn unexpectedly. Look in all directions ahead, behind, upwind, downwind, and straight up! There could be another kiter or someone’s kite above you!

Kiteboarding in waves

In addition to the rules above, there is a special set of Waveriding Rules that help clarify what to do in the waves. these rules are applied in order, example, “First to catch the wave” rule, has priority over “rider closest to the peak” rule, or, “upwind rider rule”. So the kiter who catches the wave first has priority over a kiter who catches the wave after, but is upwind or closer to the peak.

The outgoing Kiteboarder gives way to the incoming kiteboarder.

  • Situation: When riding out through the surf you are going to cross paths with the incoming kiter on the wave.Definition: In a wave area, the rules apply. The kiter coming in is riding the wave. and collision is imminent. The outgoing Kiter must give way,and not ruin the incoming kiters ride (or put him in jeopardy).
  • What to do:  The outgoing kiter should avoid riding out through the peak (waveriding zone). If you cannot go around the zone, then you must either stop, steer around, or go the other way to avoid the kiter riding the wave. It depends which way the kiter is riding the wave.

The first kiteboarder to catch a wave, has the wave.

  • Situation: two kites are trying to catch the same wave.
  • Definition: The kiter who is up and riding in on the face of wave. The first kiter to ride the wave has the wave. Usually the one who went  farther out to catch the wave.
  • What to do: The kiter on the wave first continues to ride the wave, the other kiter can go back out, or kick out ahead of the wave to let the other kiter ride through. keep an eye o the other kiter so you can anticipate his intentions. the kilter on the wave may ride upwind or downwind, it is their choice.

Where two kiteboarders catch the wave at the same time, the kiteboarder closest to the peak has the wave.

  • Situation: When two kiters catch the same wave at the same time.
  • Definition: The peak of the wave is the part of the crest the breaks first. Then as the wave progresses it is the tallest and steepest part of the wave between the open face of the wave and the whitewater.
  • What to do: The kiter riding closest to the peak should ride the rave. The other kiter that is farther out on the shoulder should keep clear, or get off the wave.

When there is no distinct peak, the upwind kiteboarder has the wave.

  • Situation: Two kiters turn onto a wave at the same time.Definition, when two kiters catch the wave at exactly the same time, the upwind rider has the wave.
  • What to do: When you have caught the wave with another rider the downwind kiter yields the wave to the upwind kiter. By either turning off the wave, or kicking out ahead of the wave. Keep eye contact with the other guy so you know their intention.

Kiteboarding Priority Rules

Kitesurfers have to cooperate with other water users, and there is a system of priority the helps establish hierarchy for right of way.

Bystanders:

  • Situation: Launching and landing on crowded beaches.Definition: Anyone not involved in kiteboarding, including, onlookers, sunbathers, picnickers, walkers, and joggers. Even fishermen, cyclists. etc.
  • What to do: Give way to bystanders, and never fly your kite over a non-participant. Do not ask an inexperienced person to launch or land your kite. Keep a safe distance from all bystanders.

Give way to Swimmers:

  • Situation: Never get close enough to come in contact with swimmers of put the at risk.
  • Definition: Anyone in the water under their own propulsion. including swimmers, and skin divers, and scuba divers. There are also special rules for Scuba divers displaying a “Dive Flag”.
  • What to do: When close to swimmers, go slow or go the other way.

Surfers, Standup Paddlers, and Rowers.

  • Situation: Any time you get close to one of these.
  • Definition: Surfers, Bodyboarders, Standup paddlers, and Rowers, kayakers, wave-ski riders, and outrigger canoes. This group are more mobile and better able to avoid a kitesurfer. But a kitesurfer must give way to all these too. This group must give way to bystanders & swimmers.

Windsurfers, and Other Sailing Craft.

  • Situation: When you encounter another sailing craft, you should give way.
  • Definition: A kite is technically a sailing vessel, BUT the lines, large window, and unpredictability, generally make them incompatible with operating close to other sailboats.
  • What to do: give way to other sailing craft, keep large buffers between you and other sailing craft. Moderate you speed when close to other sailing vessels, and ride in a predictable pattern. Never fly your kite over a windsurfer or sailing boat. you could clip their mast or worse. Otherwise you should observe normal sailing rules.

Powerboats, Jetskis.

  • Situation: when operating close to powered vessels.
  • Definition: Power boats give way to sailboats. Power is more maneuverable, and can change direction to avoid collisions. However you should exercise caution around powerboats.
  • What to do: when navigating with powerboats maintain course and speed so that their drivers can anticipate your movements, and avoid you. moderate your speed, and do your best to keep well clear of them. Boats creates wakes that can cause you to wipeout, and boats are hard objects that you could impact with, not  to mention their propellers etc. Never jump boat wakes with your kiteboard.

Commercial vessels

  • Situation: When you get close to any commercial vessel.
  • Definition: Ant vessel engaged in a commercial activity, ferries, sea planes, fishing boats. Recreation boats give way to commercial vessels.
  • What to do: Stay clear of all commercial vessels, ferries, barges, tankers, tour boats, fishing boats.

Moored boats and Capsized Boats.

  • Situation: maneuvering, navigating amongst moored or capsized vessels.
  • Definition: Any boat attached to a mooring or at anchor, or otherwise similarly restricted in is ability to maneuver.
  • What to Do: Stay Clear of all moored vessels, and capsized vessels, including windsurfers water-starting, unmanned boats, Stay clear of other kiters whose kites are down in the water or who are body-dragging.

Racing Boats

  • Situation: You are free-riding, and come across a sailing race or competition.
  • Definition: Any organized sailing event especially course or speed racing etc.
  • What to do: Stay clear of sailboat races or other organized events. If there is a kite contest, you should go ride somewhere else for the day. If you are the one in the race, you can shout aloud “Racing” to let the other sailor that you are in the middle of a race.

SAFE KITEBOARDING RULES

  • Know your own kiteboarding ability and stay with your limits.
  • Know the limits of your gear.
  • Know the weather forecast and the wind conditions
  • Know the sailing rules, local rules and riding areas.
  • Make a float and fly plan (tell someone where you are going and when to expect you back).
  • Never Kite alone
  • Do not kite between sunset and sunrise.
  • Never ride further than you can swim
  • If in doubt, don’t go out!
  • Do not tailgate other riders
  • Check your gear thoroughly before launching.
  • Do not kite between sunset and sunrise.
  • Do not launch or fly over non-kiteboarders.
  • Maintain a 2 x Kiteline length clear zone around all; Divers, Swimmers, Canoes.
  • Always use a “Kite Leash” & “Depowering Safety Device”.
  • Always use a “Quick Release” device.
  • Select a safe launching site.
  • Do not launch close to rocks or other hazards.
  • Do not launch or land at crowded areas.
  • Always announce you are launching a kite.
  • Stay clear of power lines and overhead obstructions.
  • Always maintain a downwind safety buffer zone.
  • Keep windsurfers outside the kite’s power-zone.
  • Observe all mapped kitesurfing boundaries.
  • Do not lay kite lines across anyone’s path.
  • Give way to all other water users.
  • Landing kitesurfer gives way to the Launching kiter.
  • When consideration has been given to the above, normal sailing rules apply.
  • Prevent kites from re-launching with sand.
  • Disable unattended kites.

How does a kite surf fly?

Are you wondering How does a kite fly? On this page you could easily understand how a kite fly and learn the the kite is very similar the to the wings of an airplane.

Index

I. How Wings Lift the Plane: how an airplane flights

Airplane wings are shaped to make air move faster over the top of the wing.

Lift of an airplane (itesurf) Bernoulli Equation
Lift of an airplane (itesurf) Bernoulli Equation

When air moves faster, the pressure of the air decreases (Bernoulli’s equation simlpified:  P + 1/2 * V^2 / ρ = Constant; P = Pressure, V= Velocity, ρ = Density of fluid) .

On the top of the wing the velocity of the air is more than the velocity in the bottom of the wing. For the Bernouilli’s equatuion that means that the pressure on the top of the wing is less than the pressure on the bottom of the wing.

The difference in pressure creates a force on the wing that lifts the wing up into the air.

forces of flight | forces acting on a airplane
forces of flight | forces acting on a airplane

Forces acting in a airplane during the flight are 4:

  • Lift – upward
  • Drag – backward
  • Weight – downward
  • Thrust – forward.

To have more infos on How an aiplane flights and How to control the Flight of a Plane, look at this NASA link.

II. Differences between an airplane and a kite: How does a kite fly?

Like an airplane wing, a kite can fly due to various forces acting on it.

The main differences are that an airplane has thrust while a kite has line tension and an airplane is balanced by its weight around its Center of Gravity (CoG) while a kite is balanced by its effective tow points (which can be adjusted automatically by the kite or manually by the kiter) and its weight at CoG (center of Gravity).

The forces and torques that act in a kite and how they are acting:

  • Wind Generated Forces
  • Gravity Force
  • Line Tension

To have a better idea about force acting on a kite, read the post Forces and torques on a kite.

III. Kite Design Parameters

The most easy to manipulate and highly visible kite parameters are:

  1. Aspect Ratio (AR)
  2. Airfoil Profile
  3. built-in Angle of Attack (AoA) of the kite
  4. Summary of the Aspect Ratio, Airfoil, AoA parameters.

1. Aspect Ratio

Airplane Wing Geometry Definitions | Aspect ratio, chord Kitesurf
Airplane Wing Geometry Definitions | Aspect ratio, chord Kitesurf

Aspect Ratio (AR) is approximately Span/Chord of the kite or more exactly Span*Span/Area (see more info about a Wing Geometry Definitions at this NASA link).

Since Aspect Ratio determines the shape of the kite it is the most visible kite design parameter that the user will see.

Higher Aspect Ratio kites have less induced drag (upwash and tip vortex effects)  than Lower AR kites of the same characteristics. Induced drag is inverse proportional to AR.  So when stationary at the wind window, a low AR kite can generate the same amount of pull as a higher AR kite (of the same characteristics) but as soon as we need to move the kite for more power (for jumping or underpowered situation), a higher AR kite can accelerate faster therefore get more power sooner than a low AR kite.

As a rule of thumb, a higher AR kite has a larger Power Window (the difference between min power and max power) and a lower AR kite has a smaller Power Window.

Following are the recommended AR ranges:

Kite Type Very Low AR Low AR Moderate AR High AR Very High AR
Foil 2.5- 3 4 5 5.5+
Inflatable / Arc 3- 4 5 6 7+

Note: Inflatable and Arc have spherical shape, a natural stable form, therefore their ARs are normally higher than foil’s.

2. Airfoil Profile

Airfoil has lift but also drag.

A profile with the highest lift when stationary will give the strongest pull when stationary at the wind window (AoA around 5 degrees).

A profile with the highest lift/drag ratio will accelerate faster and will generate strongest pull when flying across the power zone.  A high lift airfoil is sometime labelled a “tractor” airfoil as it will pull like a tractor at the wind window.

A high lift/drag airfoil is labelled a “speed” airfoil as it flies very fast across the power zone and generate tremendous amount of pull while doing so.  A speed airfoil may generate a lot of pull at the wind window but may not be necessary as much as a tractor airfoil.

The following table show the recommended lift and lift/drag ratio ranges:

Very Low Low Moderate High Very High
Lift Coefficient (at AoA = 5) 0.5- 0.7 0.9 1 1.1+ (Tractor)
Lift/Drag 40- 50 70 90 110+ (Speed)

Please note that these Lift/Drag ratios are the calculated ratio and not included Induced Drag.  In reality, the “real world” L/D ratios are reduced by a factor of 6 or 7.

It’s better to use an airfoil design program (such as DesignFoil at https://www.dreesecode.com/) to design, analyze and select the airfoil profile to use for the kite (for kiting purposes, the Reynolds number is around 1,000,000 to 2,000,000). Some kite designers being shy from the complexity of airfoil design and analysis, uses the rule of thumb method of changing the profile thickness/camber  for changing the lift and lift/drag characteristics of a profile.  This methodis not accurate but maybe acceptable for kites.

As a general rule of thumb, increase the profile thickness/camber to increase lift at wind window and decrease a profile thickness/camber to increase the speed of the kite.  The following table show the range of profile thickness/camber used for most kites:

Foil and Arc Inflatable
  • Thin Profile (Speed): 14% or less
  • Moderate Profile: 15%
  • Thick Profile: 16%
  • Thicker Profile: 17%
  • Thickest Profile (Tractor): 18% or more
  • Thin Profile (Speed): 8% – 9%
  • Moderate Profile: 10%
  • Thick Profile: 11%
  • Thicker Profile: 12%
  • Thickest Profile (Tractor): 13% – 14%

3. Built-in AoA

A kite get more lift with a higher Angle of Attacked (AoA) to the wind (more surface projected to the wind and also from 0 to 16 degrees of AoA, the Lift Coefficient of an airfoil normally increase to an optimum value).  Each kite has a “neutral” built-in AoA for the center of the kite and the wing tip when it is at the wind window straight over-head (with front lines and back lines of equal length).

The range of the built-in AoA is normally from 0 to 5 degrees.

Note that the wind-window angle is around 85 degrees such that the in-flight AoA of the center profile at the wind window is the sum of the built-in AoA and 5 degrees (or 90 – 85).  Note that changing the built-in AoA of the kite may also change the wind window angle such that the two will “amplify” each other to have a “double AoA” effect.  E.g., changing the built-in AoA from 2 to 0 may make the wind window angle change from 85 to 86; therefore the in-flight AoA of the kite at wind window is now 4 degrees instead of 7. It is interesting to read Peter Lynn’s Myth 1 and 2 in which he stated that the Lift or pull of the kite at wind window is proportional to the AoA of the kite and the L/D of a kite is inverse proportional to the AoA of a kite (AoA here means AoA within the “dominant AoA” range of 0 to around 20 degrees which is directly influenced by the built-in AoA of the kite).

  • A kite with a lower built-in center AoA has a larger wind window but can over-fly & luff easily and does not pull much at wind window (a Speed kite should have a lower built-in AoA around 0 degrees). These type of kites must have instantaneous AoA control for the kiter to prevent luffing and also for the kiter to “sheet-in” to get more power at wind window if needed.
  • A kite with higher built-in center AoA has a smaller wind window but generate more pull at wind window and hard to luff (a Tractor kite may have higher built-in AoA around 3 to 5 degrees for more pull at wind window)
  • An all-around kite may have a built-in AoA of 2 to  3 degrees.
  • Due to the upwash and the wing vortex phenomena, the built-in wingtip AoA of a kite can be 1 or 2 degrees higher than the center AoA.  The upwash effect reduces the AoA of the wingtip a bit so add 1 or 2 degrees to the wingtip AoA to counter balance that effect.
  • For inflatable and Arc, due to their geometry, the wingtip AoA varies much different than the center AoA and therefore the built-in wingtip AoA can be designed independent from the center AoA and the designer should add 1 or 2 degrees to the desired built-in AoA to counter balance the up-wash and the tip vortex effects.
Very Low AoA Low AoA Moderate AoA High AoA Very High AoA
Range (in degrees) 0- 1 2 – 3 4 5+
Kite Type Racing Speed All-around Wave Tractor (Wake Style)

4. Summary of the Aspect Ratio, Airfoil, AoA parameters

The following tables provide the summary of the AR, Airfoil, AoA parameters:

Low High
AR
  • Small POWER Window
  • Large POWER Window
Lift (at wind window)
  • Weak pull at wind window
  • Strong Pull at Wind Window
Lift/Drag Ratio
  • Slow
  • Fast
Built-in AoA
  • Large WIND Window
  • Small AoA at wind window (less pull)
  • Luff Easily
  • Faster
  • Small WIND Window
  • High AoA at wind window (more pull)
  • Hard to Luff
  • Slower

and their uses in different types of kite:

Kite Type/Wind Light Wind
(6 – 15 Knots)
Moderate Wind
(12 – 27 Knots)
Strong Wind
(27+ Knots)
Sled Kite Size (Foil) 16 m2 (10 m2) & Larger  8 – 16 m2 (5 – 10 m2)  8 m2 (5 m2) & Smaller
School (Stable, Low Lift, Slow) Moderate AR
High Lift
High Lift/Drag
Moderate AoA
Low AR
Low Lift
Moderate – Low Lift/Drag
Low AoA
Very Low AR
Very Low Lift
Very Low Lift/Drag
Moderate – Low AoA
Tractor (Wake Style, Wave, Gusty Wind) Moderate AR
Very High Lift
High Lift/Drag
High AoA
Moderate – Low AR
High Lift
Moderate Lift/Drag
High – Very High AoA
Low AR
Moderate Lift
Low Lift/Drag
Moderate – High AoA
All Around High AR
High Lift
Very High Lift/Drag
High AoA
Moderate AR
Moderate Lift
High – Moderate Lift/Drag
Low AoA
Moderate – Low AR
Low Lift
Moderate – Low Lift/Drag
Moderate AoA
Speed (High Jump, Freestyle) Very High AR
High Lift
Very High Lift/Drag
Moderate – Low AoA
High AR
Moderate Lift
High Lift/Drag
Low – Very Low AoA
Moderate AR
Low Lift
Moderate – Low Lift/Drag
Low AoA

 

Other Kite Design Fundamentals

  • Center profile should be selected for optimum lift and optimum lift/drag ratio (optimum as according to the type of kite requirements specified in the tables above)
  • Wingtip profile should be selected for maximum luff resistance (e.g., reflex profile).
  • For sled kites (Inflatable or Arc in spherical form):
    • A sled kite has similar projected surface of around 63% (2/pi or 2/3.14159) of the flat surface regardless any other parameters of the kite (AR, Tip/Center chord ratio, etc.)
    • If the wingtips are wide enough (effective tow points of the back lines are larger than 80% of center chord), one can reverse relaunch an inflatable or Arc by pulling on the back lines.
    • For LEI (using traditional airfoil), if the wingtip are wide enough and the effective tow point of the front lines is so forward (normally less than 15% of chord) that it reduces the AoA drastically, the kite will not fly on the front lines alone (100% depower)

More Kite Design Info

 

Flat LEI

A Flat LEI has similar structure with a classic LEI except for the following differences:

  • A flatter canopy design (however most still have a deep canopy curve compared to regular foil, to take advantage of the Sled Boosting effect)
  • A bridle system consisting of a simple but somewhat elaborated bridle system for the front lines and a very simple bridle system for the back lines.  The front bridle system has multiple connection points to the leading edge to support the leading (therefore Flat LEIs are also referred to as Support Leading Edge, SLE, kites)

The canopy is more or less equivalent to the center part of the classic LEI canopy (around 3/4 of the classic LEI canopy) and the bridle system is equivalent to the sides of the classic LEI canopy (about 1/4 or 1/8 of the canopy on each side).

Besides for the differences above, a Flat LEI design should be somewhat similar to a classic LEI in theory.  It is then just a matter of properly design the canopy and the towing points via the new bridle systems.

Unfortunately current version of Surfplan does not provide full calculation and analysis of the tow points of the bridle for Flat LEI.  So in the mean time, you have to design a flat LEI with some manual processes. Also, if you are interested in flat LEI kite design, read Bruno’s Flat LEI patent application at https://www.freepatentsonline.com/20050230556.pdf and the Flat LEI section.

 

Airfoil Database

Most kite design or foil design software come with some airfoil database; however should you want more, there are other airfoil databases and one of the most extensive airfoil databases is UIUC Airfoil Coordinates Database.

 

Kitesurfing Safety Rules

Safety rules on Kitesurfing
Safety rules on Kitesurfing

Kiteboarding is a wonderful sport that can be dangerous if you don’t know and/or respect some basic rules of sailing and if you don’t practice kiteboarding in the right conditions.

If you like to start with kiteboarding, a kitesurfing course with a qualified instructor should be done in order to be self independent and safety rules and instructions must be observed.

Preliminary checks

  • Never do kiteboarding alone: have kitesurf with a friend should be nice for the company and helpful for sharing tips and for mutual helping and support
  • Find out about the regulations on regional and municipal ordinances and on local customs, especially with regard to the safety devices required (quick release, leash, life jacket, helmet, etc.)
  • Know all the features of the spot and check the accessibility of a downwind point to be used in case of leeway
  • Always watch the weather forecast to know the intensity and direction of wind in order choose witch is the best spot for kitesurfing. Important: It is good practice to avoid kiteboarding with Offshore wind, unless a launch and recovery service is available
  • Choose the right kite size according to the wind conditions. In case the intensity is unclear, get the wind intensity with an anemometer. Never kitesurfing with an oversized kite
  • Arm (install) the kite carefully and check if safety systems (Kite Quick release and quick release of the leash) are well working
  • Never arm / run / land in unsafe conditions (avoid the presence of obstacles / bathers / other kites in the area you are kitesurfing)
  • When not in use, do not leave your kite unattended on the beach.

Kitesurfing safety rules during lanunching and landing phases

  • The majority of accidents happen when the kite is on the beach, during the take-off or at the moments before the entry into the water: in those moments it is necessary to pay close attention.
  • Re-check that lines are well armed before the kite take-off
  • Get help just from experienced kiteboarders and use the appropriate signals for take-off and landing the kite
  • Do not take-off the kite in the presence of obstacles (people, animals or things) and be carefull to have a safe distance downwind (if it is possible at least twice the length of the lines)
  • Do not stay on the beach longer than the necessary time while the kite is fliying.

Kitesurfing safety rules while Sailing

  • Don’t go in the water alone: better to be kept under control by someone or bring a device to call for help in case of need (e.g. a mobile phone)
  • Monitor the weather and any changes on wind direction and intensity
  • Maintain a safe distance from other kitesurf, windsurf, boats of all kinds, swimmers and obstacles in general
  • Be aware of your limits and possibilities: manage the time and difficulty of the sailing according to our level of experience and to our physical conditions
  • Don’t go too far from the beach: calculate a distance from the beach that allows to easy return In case of problems