Forgive me for posting this everywhere the subject of Peak4 kites comes up. But in case you only read this thread ... paste ↓
OK, I managed to get my partner to shoot some very ordinary video of me on the 5m Peak4 in 4 to 9 knots.
I really need to find someone who can video kitesurfing around here. A drone would be good but there are military airspace restrictions where we kite
So as you can see in the video the wind is quite light. If you look at the beginning where the windmeter is being held, you'll see in the distance, lower right just above the hand, a Peak4 5m kite flying while the reading is taking place. The guy on this kite weighs approx 85kg and is comfortably foiling on a Naish Large foil in this light wind. The rest of the video is myself at 65kg on an Axis 110cm Tray board and Moses 679 (990 sq cm) foil.
Now there can be arguments as to whether the wind is stronger higher up or offshore. In my experience on this day I tried to go as close to the shore as the foil and swimmers in the water would allow and only went out about 100m and the wind varied very little. Likewise flying the kite high or low didn't show much difference in the wind speed.
There are many variables with regard to wind quality as well. Some say a colder wind has more power. In this video it was a warm day approx 28°C with a water temp. of approx 24°C. However the wind is a seabreeze which is generated both by the position of a high pressure system offshore and the heat of the land mass behind the shore sucking in cooler ocean air. These seabreezes are consistent and don't have lulls of no wind. The wind is cross onshore with a long fetch, so there are no obstacles to make the wind turbulent. So it's a good location with good steady wind. Probably the best quality wind on the east coast of Australia.
I find that if the kite can lift me out of the water then I'll be up on the foil with a couple of sines of the kite. I don't think you need a huge wing, just big enough for the wind of the day. I have dropped the size of my front wing temporarily from 1250 sq cm to 990 sq cm and the effect on getting up and foiling was insignificant. (Moses wings are very efficient). However I could fly the larger foil a couple of knots less in speed on the water before it stopped foiling.
And small kites, especially Peak4's are fun. Even if the wind did drop to virtually nothing you can still fly them and drag back to shore. Something which would not be possible with an LEI kite or comparable twin skin kites.
One caveat in all this discussion. One or two knots difference in light wind can be the difference between foiling and flailing around in the water. Under 10 knots every knot matters and consistency is king. A one or two knot additional gust may be what gets you out of the water and onto the foil where apparent wind takes over. I also have an 8m Peak4 which comes out when the gusts barely reach 8 knots. Even though the 8m only adds 2-4 knots to the bottom end of your range there are enough days where this is the difference between getting up on the foil or not. It's been said that the Peak4 kites are not so much a light wind kite but are the best kites in light wind! Get your head around that