Reduce Over-Foiling When Windsurf Wave Foiling
You know the feeling. Out of nowhere your board lifts, the foil reaches the surface of the water, you lose all lift, and the whole kit crashes down. You often feel it coming. You often try to compensate. But it still happens. This article will explore changes with your gear that will help solve this problem. While there is no substitute for building muscle memory and acquiring more sensitive skills, certain gear changes make a huge difference. We'll talk a little about stance, but we will mostly focus on gear.
Front Foil - Smaller foils, both front and rear, produce less lift in general, and they do not over-foil as often. Try a smaller front foil. It will take some time to improve your efficiency so that you can get up while using a smaller foil, but it won't take long. Also, in general, foils that are higher aspect, flatter, and have less thickness will over-foil less, especially when pushed to higher speeds. Match your foil to the size of the wave and the wind speed. For example, in wind less than 18mph and in small waves I typically use the GoFoil Maliko200 which is about 1900sq. cm., is thick, cambered, and low aspect. This wing allows me to go very slow on slow waves without stalling. Once the wind gets above 18mph I switch to the GoFoil Iwa or EZ1600 which are about 1500-1600sq. cm. And over 22mph of wind I like the Iwa, the EZ1600, and the RS1300 (1300sq. cm.). The RS1300 is difficult to over-foil because of its high aspect nature, flat design, and thin profile compared to the Iwa and Maliko. However, the trade off is that the RS1300 has terrible grip and does not carve. It yaws, slides and slips through turns instead of carve. It's a lot of fun, but offers a very different riding style.
Rear Foil - The rear foil matters too. Smaller tails produce less lift. Try a smaller tail foil. Less stab angle also produces less lift, but with the sail mounted near the nose of the board it is necessary to have sufficient stab angle to counter the downward pressure of the sail weight. This is the opposite of kite foiling or wing foiling where the kite or wing provides upward lift instead of downward weight, and therefore does not require as much stab angle. When wave riding, pay particular attention to where your front foot it located, and move that front foot farther forward. Use a foot marker on your board so you know exactly where that front foot needs to be. When you are headed down a wave you will induce tremendous lift from the foil. The forward position of your front foot holds the nose down. This is extremely important. Get that front foot more forward.
Fuselage - A longer fuselage provides slightly more pitch stability than a shorter fuselage. Of all the items listed in this article the fuselage length probably has the least effect on over-foiling, but it is still noticeable. Plus there is the trade-off with maneuverability because a longer fuselage does not turn as snappy. I personally use a shorter fuselage because I like to be more turny, but if you want to reduce over-foiling then a longer fuselage will help a little.
Foil Mast - This is pretty simple. If you use a longer foil mast then you have more time to compensate for an upward thrust from the foil. The trade off is that if you do still happen to over-foil it is a farther fall, and a longer foil mast has more drag. I use a 36 inch foil mast. This seems to be the optimum length to avoid over-foiling while not increasing drag more than necessary.
Board - A shorter board catches less wind underneath. This makes a big difference. I noticed this immediately when I switched from a 7 foot board to a 6 foot board. It takes time to build the skills required to sail a 6 foot board, but it's totally worth switching when you are ready. Shorter boards require more precision to uphaul and get on foil, and they require that you bear off the wind more in order to get on foil. However, they are much more snappy and over-foil less because the wind has less surface area to push against when it gets under the board.
Mast Base Position - If you move the mast base rearward then the weight of the sail is shifted rearward. You must compensate by moving your stance (both feet) more forward in order to rebalance your weight over the foil. If you move the mast base rearward and your feet forward then these two actions combined put you much closer to the sail. The rider compartment is smaller. Your front foot is nearly touching the mast base when you're riding a wave, so your front foot and the mast base are almost like one leg, as opposed to your front foot being far away from the mast base in which case it's like two separate legs. Having your front foot and the mast base closer together gives you more stability and more sensitivity to adjust when the foil pushes up. Give it a try. You will over-foil less and you can be much more aggressive on the wave with better control.
Sail - This is probably the most overlooked piece of gear when it comes to over-foiling, but it is one of the main reasons I switched to HotSails Microfreaks (kid's sails). Because they are kids sails they are much softer. The fabric is softer, and the design and the shape makes it softer. When a gust of wind hits the sail you get more time to adjust for the gust because the softness of the sail prevents the energy of the gust from driving into the board and foil so quickly. I went from 5 batten power wave sails on my foil board to soft 4 batten (one is a 3/4 batten) kid's sails, and I immediately reduced my over-foiling. And the other benefit is that these sails go flat and depower when you are on the wave. This means that the sail will power back up more slowly because the shape of the sail has to re-fill with wind giving you an extra moment to adjust for a gust of wind. This also means that you get less counter rotation of the sail when it is flagged out. Counter rotation of the sail induces roll on the foil which means one more thing the rider has to adjust for. Less counter rotation equals more stability.
Mast - A softer mast will bend more when a gust of wind hits the sail giving you an extra moment to adjust for lift in the foil. This pairs perfectly with the kid's sails discussed above. But you can even use a softer mast with your windsurfing power wave sails to get a little extra time to adjust the foil for wind gusts. I have paired the soft kid's mast from my MicroFreak with my Ezzy Zeta power wave sail several times, and it definitely softens the sail and gives me an extra moment to adjust the foil when a wind gust hits the sail.
Each one of the items above makes a difference when it comes to over-foiling. I have tested each item individually, and they all matter. So imagine how much improvement you will make if you make ALL of the gear changes above. It is life changing when you combine them all. Give it a try! Remember, all of these improvements assume that you are riding waves with a windsurf wave foiling technique. If you are windfoiling in flatwater then some of these suggestions may help, but it won't be as applicable for that discipline.