Learning a little more about the hull. In the MAN article, Henry Struck says he was impressed with post war NACA studies of a then-new type of flying boat hull, characterized by the long, narrow hull and a planing tail. If you google on "planing tail," you can find quite a bit of material on these new long hulls. Here for example is a NASA precis on the new hull form, as applied in the Martin P5M:

"No large, multiengine propeller-driven flying boat has been developed in the United States since the Martin P5M Martin first flew in 1948. (The jet-powered Martin P6M Seamaster flying boat is described in part II.) With a gull wing of the same size as that used on the earlier PBM Mariner, the P5M was, however, a much heavier aircraft equipped with more powerful engines.

Although bearing many configuration similarities to the PBM, the P5M had an entirely new, high length-beam ratio hull with a planing-tail afterbody.

This new and greatly improved hull form had been extensively studied in both the towing tank and wind tunnels at the NACA Langley laboratory (refs. 36, 37, and 124, for example) and offered the possibility of reducing the unfavorable drag differences between flying boats and landplanes. It was found that by maintaining the product bl2 constant and increasing the value of the length-beam ratio l/b, the water drag and spray characteristics of the hull were little altered and the aerodynamic drag was significantly reduced (l and b are the length and beam of the hull, respectively).

The planing-tail afterbody ameliorated the stability problems of porpoising and skipping. As compared with more usual values of 5 to 6, the hull length-beam ratio of the P5M was 8.5, while some of the experimental data in reference 124 are for hulls of length-beam ratio as high as 15."

So this is the novel type of hull design Henry Struck was working to capture in the Sea Cat. Long, narrow, pointed step, planing tail.