I'm going off on a design tangent for a DW SUP. Basic approach is a short narrow flat water style shape to get to a launch speed to start pumping. The other hope is to prevent splashing water out front, which I'm guessing isn't helping forward propulsion!

Dims 6'2 x 24 1/2 x 4 1/4. I'll let you know if it works... BTW it's from a block of construction polystyrene. Only filler to go - weighs 3.8kgs. Boxes bonded to the half inch cedar stringers