The real stand up duck dive by l’Ours.
He does a nose dive just before the wave comes. Then the shortSUP dive and he follow it stand up thru the face of the wave. And he goes under the wave to the surface again.
You need a very low volume board for it.
SUPer : Patrice Guénolé en GONG SUP Fatal 6’3 et pagaie GONG Carbon Mix 185 cm.

Source : Team GONG SUP, first SUP real duck dives thanks to shortSUP.