To observe this suction effect, try holding a soup spoon under a stream of running tap water, and feel the round side quickly draw into the moving water, while the concave side kicks away from the water.
An interesting historical side-note is that the fin was first used by Tom Blake in the 1930’s to control the forward motion of his hollow wooden paddle boards...the same paddle boards that had box rails with an edge going around the entire bottom due to their construction. Fins and low rails were a copasetic pairing from day-one...because Blake's early "low rails" didn't hold in.
But wait, there’s more !!!
Mats also sport a flat rocker scheme, which is extremely fast, even on flat faced waves...
And yet mats are also flexible enough, longitudinally, to allow the rocker to conform to the face of the wave...with a little help from the rider. These two shots, taken just a second or two apart, show how even an old heavy canvas mat can change rocker shape at will…
Easily controlled rocker also makes riding bumpy waves a new sport!
So we had the makings of a great wave riding vehicle already in place as the basic air mat was originally built....a parallel outline, flat rocker, no fin, round rails, a flange, and some nice flexural tendencies.
With so much going for mats straight out of the starting gate, where did we go from there? And why? Highly subjective answers coming soon!