Once again, thanks to everyone for their help and insights.
As to what it takes, HP wise, to move these boats, a story:
About 8 years ago, my son, who at the time was 8, and I took a trip to maine. While there, we got a ride in what at the time was the "world's fastest lobster boat", as measured by a radar gun at the the races. Boat was a standard production fiberglass, 32 footer, 10 foot beam named the 'Capt'n Jack' built by the Crooked River Boatworks in Maine. Power was a 370 HP Yanmar diesel, which were just comming on the market and were the engines of choice for racers. Yanmars are "Twisters", that is they redline at 3600, whereas diesels like John Deers, Cummins, Cats are "Torquers", redlining at 2500 or so. The old Capt'n was built for speed in that, while it fished during the week and raced on the weekend, it was designed so that on race day, everything that had to do with work came out easily and all that was left was the basic hull and engine. The hull was built so thin that, when the light hit the sides just right, from the inside of the boat up foreward, you could actually see through the hull to the the water on the outside of the boat Unnerving at first, but seemed to be no problem as the boat still exists. In addition, the engine was not mounted foreward as is the norm, but aft, right over the center of boyancy, which is basically slightly foreward of the physical center of the boat. Hence, no long moment arm caused by the engine being up front to overcome in getting the boat on a plane. As far as the hull design goes, it was a stock semi displacement design of which many were produced by the manufacturer for mostly work purposes, i.e there were no tricks in the hull, stock as a stove bolt. [By the way, all Maine skeg boats, whether wooden or fiberglass, have the same basic underwater shape. It works, and has worked for a hundred years, for purposes of their primary mission of fishing, and no one makes a hull for any other primary purpose. So, if you look at the bottom of one manufacturers skeg boat, you won't see much difference from any other manufacturers hull. Sublte differences, yes, major, no. Therefore, the bottom of my boat is very similar to the Capt'n's]
Anyway, with the owner, me and my son on board, and with all the fishing gear also, that boat did 48mph wide open in calm water. At that speed, with that diesel roaring away, and in a narrow beam, lightweight hull, it was a heck of a ride! Only thing to do was hang on and pray we didn't hit anything submerged. Better than half of the hull was out of the water as we roared along. Felt like a thousand miles an hour.
So, that's what 370 HP can do in a boat , hull shape wise, that is very similar to mine.
What? Do I hear some unbelievers out there? Well, yes, I did ask, and was told engine was stock. I tend to believe this because there are tech checks at the races to keep everyone honest. Than again, we all know how racers are when it comes to admitting they are cheating!
My boat: The gentleman I bought it from, not being a gearhead, but only interested in where the lobsters were, didn't know much about the Ford 6 engine other than it was installed in 1979 (I doubt that it was a new engine), he having bought the boat in 1983. Since engine is gone, no way to tell what it was. However he told me that he guessed his cruise was approx. 10 knots at 2500 rpm or so and at around 3-4 GPH. He didn't much care, since he fished within 7 miles of where the boat was moored. By the way, this boat, like all lobster boats, has a hydraulic hauler run off the engine that is used to, well, haul up lobster pots. Pump runs all the time. Previous owner thought that disconnecting the pump (which I definately don't need) would have beengood for an additional 1-2 MPH cruise.
If I didn't make it clear before, boat has retired and is on Social Security--its only duties now are to run me around on Long Island Sound in style on sunny afternoons. No more heavy lifting!
Finally, many thanks to SuperMag for undertaking to get the pictures posted. I haven't a clue as to how to do it.
Have a good weekend all.