Bob,
The bow entry is different; however, there are similarities. The first thing that caught my eye was the way in which the cross beams are "melded" to the hulls. The aft inspection ports are in the same place. My transoms are slightly concave. My sail number is 69, so it's an early example of a likely low-production cat.
Looking around some more, someone suggested an "Alpha-Cat"—but the link doesn't want to appear on my computer. (Cannot find server). Maybe someone can make it appear here:
The two halyards are internal within the mast. There is no HIN number (showing). In the many years that I "drove" it solo, the extra beam is translated into awesome speed, and never—ever—came close to capsizing. Now, trying to alter one's heading was another matter entirely! Of the three cats I owned concurrently, this is the one I wish had brakes!
The boards are "working" at those speeds. The daggerboard trunks stand up about two iinches above the deck, and also made of a very thin material, suggestive of the epoxy I think the hulls are made of.
Like my Tornado, and unlike my H18, this boat is very light.
Alas, I've left myself too little time to show it this weekend, but I'll be back in September—and maybe have a better handle regarding its manufacturer.