A Nautical mile is 6000 feet even. A mile on land is 5280 feet. So the equation is,

1 knot = 1.150779 miles.

So we saw a high of 35.9 Knots of head wind which is 41.31 MPH.

"Apparent wind" is the Wind speed plus the boat speed basically when you are going up wind. So if we are traveling at about 8.4 knots = 9.66 MPH, and the wind was 41.31 against us, so the "apparent wind speed" was roughly 50.97 MPH as a max.