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leepasty said..Velocicraptor said..
At speed, how do you think drag distributes above water (body, board, etc...) vs below water (submerged foil)?
We are not going fast enough to worry too much about drag in air and it's very minimal gains. In track cycling for instance they are trying to gain 1/10th of a second. where as drag in water is massive, think how much a piece of weed on foil slows you down, yet if you held that same piece of weed in your hand fully face on to the wind while going flat out it would hardly make any difference

I raced bikes for many years, including some wind tunnel testing, and could quantify where my watts were going (wind resistance, rolling resistance, drivetrain loss, etc...), hence my interest. That said, fluid dynamics are very different topic, and I recognize my knowledge is only partly applicable.
weed on the foil vs weed above water isn't really an appropriate comparison because there is so much more surface area above water than below. Of course water is more dense than air (784 times) and will result in higher drag -- which is what you are comparing with the weed -- but below water frontal area (and parasitic drag) is so small compared to the frontal area above the water line. is frontal area above the waterline 784 times greater than below (major oversimplification)?
Just curious...