Nat's North Shore board for the Winter of 1969 was a Weber hull shaped by Harold "Iggy" Ige. Some accounts say Nat had two of these Weber boards that year in the Islands. I don't know what design variations there were between the two, if indeed there were two.
The board in these pics is somewhat similar to his Keyo Malibu roundtail from the Summer of 1968. The wide point is well forward, with a long, tapered tail. This board had a pretty severe diamond tail, and a pulled-in nose....both concessions to Island waves.
Film of Nat riding this board reveals a smooth, rhythmic up and down style of riding. Not a lot of broken track turning. It looks almost too stiff in smaller waves...the tail never wants to release. Which, again, was probably intended, given the wave riding venue.
The last I heard, Iggy's Hull was on display at the California Surf Museum in Oceanside. If you're in that area, an update on that would be appreciated, as would any board dimensions.