"What board would be the right size for me?"
This is a really good question and one that I looked at briefly as part of a broader overview in the article about choosing kite boards. OK, so now we are going to look specifically at the dimensions and the effect they have on a board for different users. There are many other characteristics of a board which will affect your choice of size, but I'll say more about them in detail in a later post.
I'm going to talk specifically about twin tips here, some of these concepts will apply to surfboards as we'll but there's even more going on there in terms of outline and volume to fit specific purposes in the waves than I want to get into here.
Firstly, you'll notice that twin tips are measured in centimeters, with the measurement being given as length x width, you might see a board described as 138 x 42. A key point to make now is that you can't really talk about a board purely in terms of its length, as you might a snowboard for instance, and there is a reason for this. Kite boards only have enough buoyancy to float themselves, so kitesurfing on a twin tip is a purely planing sport. If your not travelling fast enough for the lift force of the water pressure on the base of your board to overcome your weight, well, you sink and that's no fun. What makes a twin tip work is that there is enough surface area (length x width) to give you lift as your kite pulls you along. If you do some math and work out the surface area of some boards, you'll notice that adding a cm to width has a much greater effect on the area than adding a cm to the length. This is why noting the width is key to talking about kiteboarder size.
Consider these three sizes, 132 x 40, 135 x 41 and a 138 x 42. An experienced kiter of average weight (about 75kg) could use any of these boards to kitesurf with, so what makes one size preferable over another? Well, part of the choice is made for you by the conditions you kite in most often. If you live in a light wind area, you would tend to chose a bigger board, as the larger area will help you glide through the lulls when your kite is only just giving enough pull to keep you planing. The bigger board is also better at keeping you planing in lower speed situations such as when you are edging upwind. On the other hand, in a location where it's frequently fairly blowy, a smaller board will help you stay in control, it will be easier to edge the kite forward in the window during gusts and you won't feel overpowered so quickly.
Your own level and style of kiting is another factor to consider, if you are still in the early stages a bigger board can be helpful. It will plane with less power, so you can be on a slightly too small kite for the conditions or your weight and it will keep planing longer and be more forgiving of your kite control. Our Mr Average as a newbie might look at a 138 x 42. Freeride kiters who are looking to kite fast, hold some power and jump big, would look at smaller boards which hold a better edge in rough conditions. For this use our Average guy might choose the 132 x 40. Curiously if Joe Average was an expert kiter, looking to do unhooked freestyle he might start looking at larger boards again, like the 135 x 41 to use with straps, or the 138 x 42 to use with boots. His reasoning for this is a bit of a full circle to our beginners requirements, he needs a board which will keep planing on landing a trick with slack lines, until the kite recovers it's pull. He rides with his kite trimmed to unhook, with the bar at the chicken loop most of the time, so he doesn't have lots of ability to sheet in for extra power during lulls, so the bigger board needs to carry him through them. His focus is on flat water so it's ok for him to hold the edge on a bigger board when the wind comes up, especially in wake boots!
All this talk of the "average" kiter brings me to my final point. The average kiter is a rarity... People are heavier and lighter and need to scale their board size accordingly. A 55kg girl will want a 128 x39 for the same conditions a 95kg rider might want a 140 x 42.
With the current crop of kites and boards being so good and having ever wider range of use each year, it makes the choice of size slightly less critical than it used to be. The main thing is to buy a board that's going to be a good all round size for your body weight, ability and conditions then get out there and enjoy it!
Hopefully this might have given you a base of knowledge from which you can start your research and ask questions of our team here at 24-7 Boardsports. If you want more info on a particular board just pick up the phone (02380 894000) or come down and see us in person. Demo boards are always available. If there's something you're itching to try just give us a call and see if we can arrange it for you!