Yowzers!.... Some threads just seem to get off on the wrong foot don't they!
Ok - 25 ft, 30 knots. You're talking about a planing cat hullform to start with. I think I'm correct in thinking that the Prowler is a displacement hullform and not designed to travel that fast, but may be wrong. A displacement cat can be pushed to that speed, but it won't be as efficient as planing hull(s). The flip side is that the planing cat is unlikely to be as miserly as a displacement cat at slower speeds.
Unlike many of my esteemed colleagues here, I most definitely see the advantage of a cruising boat that is capable of relatively high speeds - though packaging it in a small, efficient package that's also capable of medium term accomodation is quite a challenge.
I've done quite a bit of coastal touring in a deep-vee monohull that is quite happy cruising at 40 knots, but it's not particularly efficient. Nor is it overly comfortable. But it does allow one to cruise quite broad areas in limited time frames and to escape unpleasant weather.
The goal then is to create a platform that's capable of reasonably high speed when conditions suit &/or are required, but also the ability cruise comfortably and efficiently at lower speeds when you're not in a hurry or when weather conditions dictate that you can't travel quickly. In generaly, productions fall woefully short on just about everycount.
The catamaran is one solution - I personally favour the displacement cat as most of one's travelling is likely to be between 10 and 20 knots. The biggest problem with a cat, though, is that they are so expensive to build / buy. For 99.9% of the population this additional expense will never be recouped in the form of lower operating costs.
My own solution, drawing below is currently under construction, offers most if not all of your stated design goals, but in a monohull. Ultimately, it probably won't offer quite as good fuel economy as a displacement cat with similar levels of accomdation, but the build cost is probably 50 - 100K less.
There are other solutions too...yours may be one of them. If you want more positive feedback, I suggest that you post some basic sketches of your idea's. I can assure you that whilst critical, the resulting comments will all be valuable.....
This one veered off from the second post onwards, as some posters prefer to nitpick or talk about their pet project, rather than contribute some useful comments, as you have just done...
Btw, if you click the links I provided in my first post, you will see the pics of all the boats under consideration and/or whose features are desirable...
I looked at monohulls first and the Cape Cruiser 23, now built as the C-Dory Venture was top on my list as a very frugal cruiser that incorporated most of my requirements, except for a self-bailing cockpit:
Additional interior photos can be found here:
http://www.c-dory.com/boats/venture_23/23 Venture photos.html
Well equipped recent models can be bought for around $50,000.00 with a 150hp 4-stroke motor that will give 22/25 knots cruising at 4/5 mpg...
The pick of the crop in terms of planning design is the 22' Morrelli/Melvin foiler that banks inwards in turns, thanks to its asymmetrical hulls, has wide chines to keep the spray down and a very efficient looking wake...
These short videos help illustrate the issue...
http://www.haasmarine.com/Action_Shots.html
In addition, the new Schionning design 750VT, a semi-displacement hull, brings some interesting new ideas to the concept, such as: "sharp entry at slow or high speeds, load carrying ability aft where the weight is usually concentrated, easy access to hulls from bridgedeck and clever location of the outboard engines, which have a clear water flow while keeping the stern platforms free. This also moves the engine weight and prop further forward, reducing potential aeration in rough seas."
This file shows how the boat is built using CNC cut Duflex panels and the unusual shape of the chines and outboard set up...
http://www.schionningdesigns.com.au/login/pages/images/VTmanualbuildsequence.pdf
The drawback of the design is that it has a high wetted area and it won't bank in turns. Also, I suspect that the claimed top speed of 30 knots with twin 140hp outboards and 1.2 liter per nautical mile (better than 3 miles/gallon) at a non-stated cruising speed, mentioned by one of the outfit building the boat are exaggerated...
What I'm trying to achieve is to amalgamate all the most desirable design features of these boats into one super duper pocket catamaran, as described in my opening post and all comments focused on the subject at hand are welcome...
Although my tastes, for the present, tend somewhat smaller- trailerable beam, light enough to pull with a vehicle that doesn't suck back 20+ L per 100 km, and would spend a lot more time on canals and lakes than on the ocean. I have one on the drawing board now (a competitor to the light planing cruiser some of you have heard me talking about) that's 8 m on the waterline, 2 t nominal full-load displacement, and would max out at 20 knots with 20 kW effective (so about 35 kW engine power, or 2 x 20-25 hp outboards). Probably not as efficient per tonne per knot as what Manie and Mas have been talking about, but different design constraints too.
