On CRP5:      Put centre dot top centre of large square grid, rotate to wind direction (210º) under the heading index and draw a line straight down from the centre dot.  

Rotate to put runway alignment (047ºM) under the heading index and move centre dot down to 10kt line on the grid.  

Draw a line along the top of the grid; this represents the 10kt tail wind.  

Rotate to put the wind direction under the heading index and read wind speed where the two lines intersect (11kts).