Circle hydros were 3 pointing on the prop back on the early 50s. Slo Mo Shun was the first unlimited 3 pointer in 1950. The problem with hydros in general is they accelerate much slower than displacement hulls unless they have an over abundance of power to weight and length so they can blow themselves out of the water. So drag hydros were then last to go to full 3 point hydro designs because they were actually slower than the displacement hulls. The first top eliminator classes were regular flat bottoms, then they went to "hydrobouts" or "runaplanes" that were transitional flats with trainer wheels.