Glossary of Terms

Hydrofoil Terms

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team Hydrofoil Glossary of Terms

What is a Mullet Grab? Who is Foiltech? What is a Scorpion? Well hopefully all of those questions will be answered below. This is a detailed glossary of terms that are related to Hydrofoiling. If you have any input of changes that you feel should be added to the descriptions below, please contact us and let us know. These are listed in alphabetical order. All 'Tricks' are highlighted in Yellow:

2 Piece Billet	Foil assembly made by SkySki that is 2 pieces of 6061 T6 aluminum that has a mortise and tenon joint at the point where the strut meets the fuselage and is welded or bolted.
360 (aka 3)	See Heli
6061 T6 Aluminum	Type of aluminum used in beginner to intermediate level foils. Not as strong as 7075 but less expensive.
7075 Aluminum	Type of aluminum used in intermediate to advanced foils. It is stronger and therefore can be made thinner to reduce drag and increase performance.
Air	a) Used to describe a trick that is done in the flats without the use of a wake. b) describes the distance between the lowest point of the foil and the surface of the water.
Air Backside Roll	A backside roll that is executed out in the flats with no wake. See Roll
Air Chair (AC)	Manufacturer of Hydrofoils. One of the 2 original companies.
Air Front Flip	A front flip that is executed out in the flats with no wake. See front flip.
Air Frontside Roll	A frontside roll that is executed out in the flats with no wake. See Roll
Air Gainer	A gainer that is executed out in the flats with no wake. This is most commonly the first invert and is also referred to as just a gainer. See Gainer
Air Jump	A jump that is executed out in the flats with no wake. Also commonly referred to as just jump. See Jump
Air Roll	A roll that is executed out in the flats with no wake. See Roll
Angle of Attack	Describes the angle at which the wing is attacking or flying through the water. By making a rapid change to the angle of attack the wing becomes a 'built in' ramp so to speak and gives you the upward momentum to jump. This is basically the purpose of the dip prior to a jump.
Ankle Leash	Safety leashes around the ankles on some foot bindings. They are there in the event your feet come out of the bindings to prevent the T-Bar from coming around and possibly injuring you.
Anodize	An electrolytic passivation process used to increase the thickness and density of the natural oxide layer on the surface of metal parts. Anodizing increases corrosion resistance and wear resistance. Type II anodizing is recommended for Hydrofoils and eliminates the need to polish. In aluminum anodization, this aluminum oxide layer is made thicker by passing a direct current through a sulphuric acid solution, with the aluminum object serving as the anode (the positive electrode). The current releases hydrogen at the cathode (the negative electrode) and oxygen at the surface of the aluminum anode, creating a build-up of aluminum oxide. This oxide layer increases both the hardness and the corrosion resistance of the aluminum surface. The oxide forms as microscopic hexagonal "pipe" crystals of amorphous alumina, each having a central hexagonal pore (which is also the reason that an anodized part can take on color in the dyeing process). The film thickness can range from under 5 micrometres on bright decorative work.
Around the Boat	This is done by cutting out wide to one side and then having the boat driver turn back in to and underneath the rider while the rider continues around behind the boat. The boat then continues in the opposite direction with the rider. This takes good coordination between the driver and the rider.
B3F (Foiltech)	Wingletless front wing developed by Foiltech
Back at Cha	Similar to a Shifty except this trick is done out in the flats and the rider turns away from the boat.
Backside
Ballast (Tanks)	Tanks onboard a boat designed for filling with water to make the boat heavier in the water thus creating a larger wake or roller.
Baseball Grip	Holding the handle in the same fashion as you would hold a baseball bat. Alternative to Palms Down Grip.
Bat Wing	A term used to describe the trailing edge design of some front wings. The trailing edge resembles the shape of the curves in a bats wing. A double bat simply means there are two curves on each side of the wing.
Bernoulli's Principle	The Bernoulli principle is expressed by an equation (known as Bernoulli’s equation) which states that for a given volume of fluid, the total energy remains constant due to the principle of the conservation of energy. This means that when a fluid is in relative motion, the energy is split into the ‘parts’. The sum of these parts will not exceed a certain value which will remain constant as long as the external conditions do not change. We shall start by looking at a wing cross-section designed as it was meant to be used - to produce lift on an airplane. As the wing moves through the air it splits the air into two streams. One stream travels over the wing and one travels under the wing. Because of the way the wing is shaped, the distance across the top of the wind is greater than the distance across the bottom of the wing. This causes the air flowing over the wing to move faster than the air flowing under it.
Bernoulli's Principle (cont)	As we have seen above, Bernoulli’s equation states that a faster moving fluid has a lower pressure than a slower moving one. This means that the faster moving air above the wing has a lower pressure than the air flowing under it. This pressure difference causes the wing to move towards the area of low pressure i.e. in an upwards direction. This phenomenon is known as lift and this is what keeps planes from falling from the sky. The lift on a wing is proportional to its’ area - the larger the area, the more lift is produced.
Bindings	The part of the foil that your feet are placed in and secured by either heel straps or footstays. The bindings are mounted over the foot pads.
Blender	A wrapped backside roll.
BnC (Ball & Chain)
Board	The part of the foil assembly that the seat tower and foot pads attach too. Also commonly referred to as a deck. The most common type currently available is a foam filled board. There is limited availability of honeycomb filled and carbon fiber boards from a few select manufacturers.
Body Slide	Similar to a Power Turn except you are more stretched out and your entire side and arm are on the water.
Bolt Through (T-Bar)	Describes a T-Bar that the bolts have to be removed in order to take the T-bar out of the seat tower. Bolt through T-Bars do not require the use of a safety pin as with the fork top T-bar. Alternative to the fork top.
Bottom Out	Describes what happens when the front wing unexpectedly exits the surface of the water during normal riding. When the wings exits the water it looses all lift and immediately crashes back down until the board hits the water, thus the foil bottoms out before regaining flight. Also referred to as pot-holing. Also see pothole.
Butt Trax	See Trax Pad
Capt Mod	This refers to when someone modifies there own seat tower with the carbon fiber top plate and 8 rubber bushings as was designed in the Capt seat.
Capt Seat	A seat tower that was developed by Capt Mike Woodruff. It utilizes a carbon fiber top plate with 8 rubber bushings that together act as a shock absorbing seat without the extra weight of a shock. The tower structure itself is also a custom design.
Cast Foil	An original design for manufacturing T-bars. The process uses lower quality aluminum and it is then melted and poured in to a form. Once cooled it is removed and polished. This is an inexpensive way to produce T-bars but you can not achieve the best quality with this method.
Cinch	CinchMax is an aftermarket manufacturer of Hydrofoil products. Cinch belt, Cinch release, footstays, etc.
Colonel Sanders
Combo (Swoop / Sinker)	A combo is any number of tricks (more than one) done in succession. Combos can be done anywhere and with any variation. There are 2 types of combos: See Swoop and Sinker.
Death Blade	Wingletless double bat front wing developed by Foiltech
Deck	See board.
Deep - Vee	A handle that is designed to fit around the nose of the board while in the water. Since the nose of the board fits between the handle it helps balance the rider and pull them up more evenly and eliminates them from having to deal with which side of the board to put the rope. A deep - Vee handle is the best way to teach a newbie. As soon as a rider is comfortable getting up you should switch to a regular handle.
Dip	This is describing the "V" or "U" shaped motion made prior to a jump. You are basically changing the angle of attack of the wing on the water and loading the line. The faster or quicker you can do your dip the bigger the jump.
Dismount	Completing a trick without the handle or with no intention of riding it away. The rider will initiate or start the trick and then at a key point drop the handle to focus on learning the trick.
Dive	A characteristic of a foil that wants to continue to loose altitude toward the water as you edge or cut out. This is indicative of a foil that needs a positive shim or lift added.
D-Nut	The flat nuts used to bolt a seat tower to a board.
Double Bat	See Bat wing
Double D	A double backflip or gainer. Usually done as a dismount due to the fact that this trick also requires an experienced boat driver to help with line tension.
Drag	A combination of aerodynamic or hydrodynamic forces which tends to reduce speed. Dull leading edges, tarnish & material are some contributing factors to drag.
Evo (Evolution)	A seat tower designed by SkySki that uses a hinge mechanism on either side and a G-10 flex plate on top for shock absorbsion.
F37 (Foiltech)	Foil assembly made by Foiltech
Face Plant	See Scorpion
Falcon	Wingletless rear wing developed by Xtreme Foils
Fashion Air	During a jump you put one hand behind your head or neck - silly face optional.
Flat Front	Describes a front wing that is straight across on the trailing edge. It has no cut outs or shape to the trailing edge.
Flats	The area outside of the wake where there are no rollers.
Flex Seat	A seat tower designed by SkySki that uses a hinge mechanism in the front and rubber bushings on the rear for shock absorbsion.
Flip Flop	An air front roll to an air backroll done sinker style.
Flip Flop Flip	An air front roll to an air backroll to a air front roll done sinker style.
Floater	The act of releasing the handle and re-grabbing during a trick.
Flowbee
Fly-In	A Class 'F' tournament sanctioned by the USAWS and the USHA. It is a fun - non competitive event where riders from all over and all skill levels can get together and ride. A Fly-In is a great place to see all riding styles and to try new equipment before you buy it. Pros and newbies are commonly on the same boats.
Flying Chicken	Cut out wide and glide with slack in the rope then flap arms.
Flying Dutchman	A Gainer with a nose grab during the trick.
FoilTech (FT)	Hydrofoil manufacturer from Australia.
Foot Pads	Foam pads that are underneath the bindings. The help keep you feet in place and comfortable.
Foot Pressure	Riding while pressing down or pushing down on the balls of your feet. If a foil is too hot or has too much lift you may need to increase your foot pressure to keep it from climbing out of the water.
Footman Loop	Brackets mounted to the seat that the belt is attached too. Brackets are built in and do not move. They are fixed in one position. Alternative to swivel loops.
FootStays	Double locking straps used to safely secure your feet in the bindings.
Fork Top (T-Bar)	Describes a T-Bar that the bolts do not have to be removed in order to take the T-bar out of the seat tower. Fork top T-Bars do require the use of a safety pin since the T-bar could accidentally slide out while riding. Alternative to the bolt through.
Frame Count	A consistent method for comparing and measuring the height of a jump. Video is shot or captured at 30 FPS (frames per second) and the first frame where the wing is exiting the water is counted as frame number 1. The first frame when the foil re-enters the water is counted as the last frame. So far this is the best method for accurately measuring height.
Front Flip (Air / Wake)	A more advanced trick consisting of starting with a very steep jump then initiating a forward rotation to complete the flip.
Front Wing	The larger of the two wings on a foil assembly. The front wing is the load-bearing wing of the foil. Front wings are available in winglet or wingletless version. There are numerous variations of shapes and sizes also available.
Frontal Scorpion	See Scorpion
Frontside
Fuselage	This describes the bottom portion of the T-bar that the wings actually bolt to.
G-38	Foil assembly made by Geno Yauchler
Gainer (Air / Wake)	A gainer is a simple backflip. Straight rotation end over end. This is typically the first invert a rider will learn since it can easily be taught at slow speeds and without the need for line tension. A gainer can be executed as an air gainer (in the flats) and more commonly called just a gainer or at the wake - wake gainer.
Ghetto Combo	360 to air backroll combo
Glide
Glitch	This describes when a foil does something that is un-characteristic. Meaning it wobbled or jerked to one side or the other. This typically happens when the rider is passing through the wake, prop wash or is on edge cutting out in to the flats. Glitches have been known to be severe enough to throw a rider off of the foil.
Grab	Grabbing any part of the hydrofoil during a trick (i.e. seat, board, etc.). Also see Mullet Grab & Strut Grab.
Handle Pass	The act of passing the handle behind your back from one hand to the other during a trick - usually a spin. The alternative to an Ole'.
Heel Straps	A rubber strap that is used to secure your feet in the bindings. These are commonly replaced with footstays.
Heli	A 360° rotation while in the air. Can be preformed as a frontside or backside rotation. Variations are handle pass, wrapped or ole'. Other common names are: 3, 360 or spin. The Heli can also be performed in conjunction with another trick (i.e. Mobe, BnC & KGB).
Hot	A term used to describe a lot of lift in a foil. Not to be confused with power or pop.
Hunt	A foil is said to be 'hunting' when the leading edges are too sharp and the foil tends to porpoise or search up and down for level flight. This can be corrected by using sandpaper to dull the leading edge slightly.
Invert	Describes a flip of some type. More specifically to become inverted is to have your feet (or foil in this case) over your head.
Jump (Air / Wake)	A jump is just that. Jumping the foil out of the water. This is accomplished by changing the angle of attack of the wing on the water either by leaning back slightly or doing a dip. It can be executed out in the flats or at the wake. Jumps are the very first steps before learning any tricks.
Kangaroo Jumps	A series of repeated jumps one right after the other. For all practical purposes, Kangaroo jumps are nothing more than a combo of jumps.
KGB
Kicker	This term is used to describe an on-coming wake from another boat.
Lazy Boy	A variation of the Floater. During the release you place both hands on the back of your head.
LE38	Foil assembly made by SkySki
Leading Edge	The front or forward edge of the wing or T-bar. You do not want the leading edge as sharp as the trailing edge or the foil will tend to hunt.
LEX	Foil assembly made by SkySki
Lift	A mechanical force generated by a solid object moving through a fluid. In Hydrofoiling terms; the foil wants to climb or ride up to the surface of the water. Also see Bernoulli's Principle.
Line Tension	Describes how tight the line is. The rider uses line tension to his/her advantage to help with tricks and/or rotation during a trick.
Loading the Line	Increasing the amount of tension on the rope. See line tension.
Mach 2.5 (SM 2 / SM 2.5)	See Schwing
Maxx-Air	Wingletless front wing developed by SkySki
McThruster	During a jump, drop the top of the board with your hips thrust forward and shoulders back.
Method Air	During a jump, grab the board between the foot pads and the seat tower with either hand.
Method Floater	Same as a method air except you release the handle during the trick.
Mobe
Moon Pie	See Oreo
Moorebius	Wake back roll and backside 360
Morbius
Mullet Grab
Nancy Floater	Similar to a Method Air except you grab the board with both hands at the same time.
Negative (Shim)	Means to decrease or remove lift. Adding a shim in the rear of the rear wing will decrease lift. With the machined shims you will hear them referred to a minus 1, minus 2 or minus 3 these are numbers that reference the thickness of the shim. Opposite of positive.
Neutral	Describes the flight characteristics of a foil that does not want to climb or dive. It wants to fly straight and level.
Newbie	Refers to someone new to the sport. It in no way is a derogatory title, it simply means you are just learning. Sometimes also referred to as a noob.
Non-Stretch	See Zero Stretch
Nose Grab	Grab the nose of the board during a trick with either hand.
Off Side	See Switch
Ole'	To pass the rope/handle over your head during a Heli. The handle stays in the same hand throughout the entire trick. Alternative to the handle pass.
Oreo	A front flip to backroll (or front roll) to front flip.
Palms Down Grip	To hold the handle with both of your palms facing in a downward direction. Alternative to the 'baseball' grip.
Parallel	This term is used to describe a wake from another boat that is travelling in the same direction as you or 'parallel' to you.
Polish	A foil assembly that is not anodized will need to be polished periodically. If the metal begins to discolor or tarnish it will dramatically effect the riding characteristics of the foil. Usually felt by the increase in drag and reduced lift.
Pop	A foils ability to launch or climb out of the water rapidly. A foil is said to have a lot of pop if it reacts very quickly to the initiation of a jump. It is similar to power but not to be confused with lift.
Porpoise	Describes the upward and downward motion of the foil in rapid succession. Similar to the motion a porpoise makes as it swims through the water. Some of the more common causes of this are; a wing that is hunting, a wing that has too much lift (too hot) or has too little lift (negative).
Positive (Shim)	Means to increase or add lift. Adding a shim in the front of the rear wing will increase lift. With the machined shims you will hear them referred to a plus 1, plus 2 or plus 3 these are numbers that reference the thickness of the shim. Opposite of negative.
Pothole	Similar to hitting a pothole while driving your car. Describes an imaginary 'hole' in the water. See bottom out.
Power	Similar to lift except it better describes the amount of instant lift that can be used by the rider. Also see Pop.
Power Turn	A low slalom turn with weight supported on one hand (surf turn).
Prop Wash (Wash)	The turbulent water directly behind the boat in the center of the wake. Since the foil is actually flying through the water, this area is not the best conditions for riding.
Pump	See Shock Pump
Pwnage	A term used to express one's act or state of elite performance. Pwnage stems from the word "pwn" which is a typographical error of the word "own". The "p" replaces the "o" because during the frenzy of gaming, the player has no time to correct any spelling mistakes. This word is traditionally used by experienced Hydrofoilers, videogamers, and others involved in computer minded social or work groups.
Quiver	Nose of the board rises and falls several times during a jump.
Razorback	Wingletless front wing developed by SkySki
Rear Wing	The smaller of the two wings on a foil assembly. Most commonly the rear wing is shimmed to adjust lift. Some rear wings can even be adjusted forward or back to change the wheelbase of the foil thus changing the quickness (how fast the foil reacts). Rear wings are available in winglet or wingletless version. There are numerous variations of shapes and sizes also available.
Release (manual / automatic)	A device that is used in the line that is operated either manually or automatically that will release or un-hook the tow line from the boat in the event the handle get caught on something or someone. A manual release requires someone with knowledge and experience to watch the rider and anticipate what is happening in order to release prior to any damage. An automatic release is set to a pre-determined setting (pounds of pull) and will release if it exceeds that amount. A release is a must in learning certain tricks (i.e. spins, front flips, mobes, etc.).
Rock Tower	A seat tower with no shock absorbing capabilities. A solid seat with only a foam pad.
Roll (Air / Wake) (Frontside / Backside)	An off-Axis gainer. Also referred to as a two-handed gainer.
Rollers	Waves created by a boat moving through the water. Also see Wake.
Safety Pin	Pin used to prevent T-Bar from falling out of a fork top setup.
Schwing	Front wing developed by Xtreme Foils
Scorpion	This describes what happens when you get pulled out the front or catch the front wing on the water. The board will grab (stop forward motion) while fully extending or stretching your body backwards.
Seat Pad	The foam pad that is on top of the seat tower.
Seat Tower	The part of the foil assembly that bolts to the deck and the rider sits on. The T-Bar also attaches to the seat tower from the bottom. There are several variations of the seat tower. See shock tower, capt seat, flex seat, evo & rock tower.
Shifty	A trick that is done during a jump. While in the air the rider twists and turns the board slightly to one side and then returns back straight just before landing. The rider typically releases one hand during this trick.
Shim	A thin piece of material used to change the flight characteristics of a wing. Common materials are guitar picks, old credit cards, coins or washers. There are some machined metal shims available for some foils. Typically the rear wing is shimmed positive to make the foil hotter (add lift) or negative (remove lift).
Shock Pump	A small hand pump used to inflate the shock absorber on a shock tower.
Shock Tower	A seat tower that has a shock absorber incorporated in to the construction to help absorb the impact of hard landings.
Sick	Slang term to describe something that is cool, wicked, good or awesome.
Sinker	Describes a style of combo. The second (or following) trick is completed after a momentary delay in between. In a sinker style combo the prior (or first) trick is completed in such a way that the foil enters the water at a flat or upward angle - just as if you where doing a single trick. Alternative to swoop. Also see Combo
Skidder	This trick is when the rider rides the foil to the top of the water or maximum height before the wings exit the surface and then leans back thus riding the foil on the surface as opposed to beneath the surface.
Skidder Floater	A combination of doing a skidder and a floater at the same time.
SkySki (SS)	Manufacturer of Hydrofoils. One of the 2 original companies.
Smoke & Mirrors	A wrapped gainer and you unwrap during the trick and land.
Soft Tail	See Flex Seat
Speedball	A double front flip.
Spin	See Heli
Spinner Floater	A variation of the Floater. During the release you spin the handle at least 360° before you regrab.
Spray Line	The area just outside the wake where the spray from the hull of the boat creates a 'line' in the water. Often used as a target to aim for when doing a dip at the wake.
Stealth	Foil assembly made by Air Chair
Stiffy	Jump with the board horizontal to the water and the bottom of the board facing the boat.
Stomp	See Dip
Strut	The vertical portion of the T-bar. See T-Bar
Strut Grab	Grabbing the strut or T-Bar during a trick.
Stubby	Foil assembly made by Air Chair
Submarine	This trick is done in combination with an invert and requires an experienced boat driver. The invert in intentionally under-rotated and the entire foil and the rider land at a downward angle and become completely submerged momentarily. The boat driver slows the boat down dramatically at the point of entry and then after the rider is completely submerged brings the boat back up to speed pulling the rider back up.
Suck Down	A term used to describe when the board gets stuck to the water. There are several theories as to why this happens and what causes it. It is most common in cooler water. Usually a rider can either lean way back to release to board or move the the prop wash behind the boat to break the suction.
Swinging Door	Wrapped air jump to floater while unwrapping.
Switch	This is typically the opposite of your 'natural' or 'comfortable' side. Most all riders have a side of the wake that they are more comfortable riding and learning tricks. When tricks are performed on the opposite side it is said to be switch. Also referred to as your off-side.
Swivel Brackets	Brackets mounted to the seat that the belt is attached too. Brackets are built in such a way to swivel forward or back depending on the riders seat position. Alternative to footman loops.
Swoop	Describes a style of combo. The second (or following) trick is completed immediately after the prior one with no delay in between. In a swoop style combo the prior (or first) trick is completed in such a way that the foil enters the water at a downward angle thus initiating the immediate start of the next trick. Alternative to sinker. Also see Combo
T-Bar	Describes the vertical part of the foil and the fuselage. At the top is connected to the seat tower and the wings are attached to the fuselage at the bottom. Also see strut.
TC Mod	Tim Cameron Modification to the SkySki Flex Seat. The mod is to replace the rubber shock bushing with valve springs from an engine. The mod increases the amount of seat travel and flex.
Trailing Edge	The rear or back edge of the T-Bar or wings.
Trax Pad	A type of thin padding that is used on top of the foam on most seat pads. It is also available in large sheet for other uses.
Tuning	The act of sanding on the T-bar or wings to improve the flight characteristics. Can also be done to correct any flaws or repair damage from hitting something in the water or hooking the handle on the foil.
Turbulence	This describes un-clean water underneath the surface created by the prop wash of the boat. The foil is a wing that needs clean (free from bubbles, etc.) smooth water to fly properly. Turbulent water has the same effect as air turbulence in an airplane.
Undertaker	During a jump you reach between your legs and grab the handle while releasing with the first hand.
USAWS	United States of America Water Ski Association
USHA	United States Hydrofoil Association
V-38	Foil assembly made by Air Chair
Wake	The 2 waves or rollers that are created by the towboat as it moves through the water.
Wake Backside Roll	A backside roll that is executed at or on the wake. See Roll
Wake Front Flip	A front flip that is executed at the wake or on the wake. See front flip.
Wake Frontside Roll	A frontside roll that is executed at the wake or on the wake. See Roll
Wake Gainer	A gainer that is executed at or on the wake. See Gainer
Wake Jump	A jump that is executed at or on the wake. See Jump
Wake Roll	A roll that is executed at or on the wake. See Roll
Wash	See Prop Wash
Wheelbase	Refers to the length or distance between the front and rear wing. Similar to a car in the aspect that a short wheelbase car will turn and/or respond faster than a long wheelbase car.
Winglet	The part of a wing that turns down at the tips. Winglets add to the horizontal stability of the wing. This is a personal preference only. Alternative to wingletless.
Wingletless	A wing that is flat or does not have the tips turned down. A wingletless wing is not as stable as a winglet wing but it typically regains flight sooner. This is a personal preference only. Alternative to winglet.
Wrapped	A trick that starts with the handle wrapped around behind your body.
Wrecking Ball	A 720° spin done at the wake. The first spin is started from the wrapped position and the second spin is done with a handle pass. This trick was invented by Jeremiah Newman.
Xtreme Foils	Hydrofoil manufacturer from South Dakota.
Yin Yang	A backroll (or gainer) to air front flip done swoop style.
Yin Yin Yang	A double backroll swoop (or double gainer swoop) to air front flip.
Yo-Yo	This is a combo trick and is started with a frontside Heli with no handle pass or Ole' - landing with the handle wrapped. Followed immediately by a wrapped backside Heli landing un-wrapped.
Zero Stretch Rope	Spectra or similar. The rope will not stretch under a load. Best for Hydrofoiling to prevent recoil in to the boat and being pulled out the front on the foil. Also helps control line tension.