The most important piece of equipment to kite-hydrofoil is obviously a hydrofoil (or sometimes called a foilboard). For a long time the supply of a commercial kite hydrofoil was very limited, but there has been an explosion of options the last few years. You can check the list of commercially available ones that I know of HERE.
Hydrofoils are improving quite a lot the last few years. Getting hydrofoil performance up takes a lot of research and top materials, so it is understandable that prices for good hydrofoils are very high.
Until now, hydrofoils have generally been either classified as slow/beginner, or fast and advanced. I think this classification will stay, but I do believe we will see hydrofoils with some unique characteristics popping up. A rider that has been riding for a few years but is not into racing might require characteristics that is neither good for beginners or racers. A rider that is privileged enough to be hydrofoiling in waves often will also have other unique requirements. Generally though, a beginner will be quite happy with a slow low aspect hydrofoil, and an advanced rider will be happy with a good racing hydrofoil even if he is not into racing. Lets look at some scenarios:
A SLOW, LOW ASPECT RATIO DESIGN (TYPICAL BEGINNER FOIL)
For beginners, a hydrofoil that foils at lower speeds makes learning much easier. If the foil has a bit more drag (either from a thicker keel, or worse finishing, or from the induced drag caused by a lower aspect ratio) it actually helps you to control speed and focus on just getting your muscles used to the new sport of hydrofoiling. I used a slow low aspect hydrofoil for a long time and in big waves and rough conditions. Once I got used to faster hydrofoils however, I did not want to ride a low aspect ever again. Generally, these designs do not need to be as stiff and is slightly easier to produce than a high performance hydrofoil, so they should be less expensive. Since the high price is a big hurdle for most people to get into the sport, getting a lower price low aspect ratio hydrofoil to start with is a good idea but not necessary. With good more advanced designs these days one can easily start off with a more advanced design from the start if price is not an issue.
Here is (from left to right): a slow beginner foil, a medium aspect all-round cruiser, and a racing foil.
A FAST HIGH ASPECT RATIO RACING DESIGN
Racing is what took hydrofoils to the next level. The parts had to become more streamlined, but at the same time the stiffness had to increase to avoid vibrations and lack of control when fully powered. A racing hydrofoil is more difficult initially, but so much more fun when you are used to it. Small high aspect ratio wings is what characterize these foils, and I am sure most people witching racing events will see that only a handful of hydrofoils compete at the top level.
A HIGH/MED ASPECT RATIO DESIGN FOR ALL ROUND CRUISING
This freeride foil has a longer fuselage that could be good for beginners
Another type of freeride foil that is good for waves and freestyle (and only weighs 1.5kg!)
Most people will get good at hydrofoiling, and will want a faster more advanced hydrofoil eventually. However, they do not necessarily want to race, as long as their performance is close to a full on racing foil. I have found that to get that extra 3% of performance from a hydrofoil, one might need to sacrifice 30% of its handling characteristics. For a person not racing, I would rather have excellent handling and speed. That is what the advanced all-round hydrofoils cater for. I think a lot of unique styles will develop. Most high aspect ratio hydrofoils that are not on the podium in racing will probably fall into this category. I think they would generally be easy enough to learn on, but there could be a lot of differences within this category.
A DEDICATED WAVE HYDROFOIL
My attempt at a good wave hydrofoil.
I believe that hydrofoiling in waves is the next aspect of the sport that will develop in the future. For waves (which generally goes hand in hand with large chop conditions) I find that a very stiff, rather fast, hydrofoil is required with less pitch stability than the average hydrofoil. Too much pitch stability can be terrible when you cruise over large chop and waves at speed. A shorter fuselage design, wings with a wide speed range, and good handling characteristics in terms of yaw/roll interaction is what is needed for a good wave hydrofoil. Here is a picture of my attempt to design a good wave hydrofoil (notice the long keel and short fuselage).
Obviously you will also need your normal kiteboarding gear: kite, harness and wetsuit if needed.
Initially, I used no protective gear when hydrofoiling despite occasionally feeling that I should get some protection. After being knocked on the head and numerous hard wipeouts, I now always wear a helmet. An impact vest is probably also advisable.
The board for a hydrofoil is only used to help the rider get up onto the foils. One could actually not use a board at all, and simply mount a hydrofoil to your feet somehow and you can go hydrofoiling. Moses was the first to sell a board that is only big enough to put your feet on and mount the hydrofoil on. You can hardly see a board at all:
However, having a board with some float is definitely worth it. You will be able to take off in much lighter wind, and more importantly: you will be able to change your feet when you jibe so that you do not have to ride toe side coming back all the time.
Since the sport is still so new, and there is so many different reason for wanting a specific board, the size and shapes of hydrofoil boards vary tremendously. The most common hydrofoil board size and shape seems to be around 150cm x 50cm, with enough thickness to give it good buoyancy.
Most people start off by taking their existing directional board and mounting their hydrofoil to it. The board obviously need to be adapted to take the hydrofoil. Most hydrofoils have a rectangular flat plate at the top, and uses 4 screws to screw the hydrofoil onto the board like this:
This mounting system is quite common since it is the easiest way to mount a hydrofoil to existing directional boards. It normally only requires four holes to be made into an existing board. However, unless the board that you are using is a very old and you won’t mind getting it water-logged, it is important to seal off the holes so that water cannot get into the core of the board. And since you need to get the board wet with resin and fiberglass, you might as well reinforce the board around the mounting area and decrease the change of the board breaking due to the increased loadings caused by mounting it to a hydrofoil.
A neater mounting system that allow you to connect the hydrofoil onto the board faster, is by using a fin box. The hydrofoil basically mounts like a very large windsurf fin. Obviously the fin box must be strong enough since a hydrofoil has a lot more forces on it than an average windsurf fin, but a tuttle box has proven itself to be strong enough and is becoming quite common on hydrofoils.
I suspect most hydrofoils will progress to making use of a tuttle box for the simplicity and since tuttle boxes are easily obtainable and quite universal. However, the plate with 4 screws will still be around for a while, since most boards are too thin to allow it to take a tuttle box insert.