Gary, Your last statement is a very thought provoking one."how much extra power (and fuel) would a seasoned traveller be prepared to accept for cruising conveniences?" What you see go in the tank is an obvious cost and ecological concern. Less obvious is what we build the boat from and then add to it. By trying to save weight one normally requires expensive exotic materials or a reduction in the extra gadgets we add to a boat. The gadgets certainly add to our cost of ownership, often more than fuel and the exotic materials perhaps. Every time we add another gadget we also add the fuel to supply the power to make it, truck it, warehouse it, service it, install it and so on. One then has to balance the cost of our boats fuel against the rest of life's gadgets. Hey, I'm a self confessed gadget freak and diesel head like many but also try to balance the real expensive gadgets with, is it really needed? e.g. Satellite TV on a boat is a prime example. Pop-up TV lifters also cracks me up. What a gimmick! We all have to enjoy life in our own ways and remember the big picture in the fuel equation, so long as we are taking the risk to push the Powercat barrow and save 30-50% of the normal powerboats fuel bill, we are way ahead of the eight ball. Speaking of hull shapes creating resistance and all the fancy physics laws, we have changed our views on hull design in the past few years from practical ocean going experience. We use to have slim displacement hulls but found when fully loaded for long passages the designers predicted economy was way out the window. After investigating what shallower wider hulls performed like loaded light and heavy from real time data, we have decided to head that way for our future boat. Our new 55ft baby's just posted on http://www.adventurebaypowercats.com/ Prelim glimpse only in the powercat section. Hope to start her early to mid next year with fat efficient hulls! Ones that will make life comfortable aboard but we may have to sacrifice the electric pop-up TV mechanism for the extra fuel we use over a 5 year period...we can manage it. Or I may have to wash the boat myself to offset the extra $1000 P.A. fuel bill... You can see where I'm going can't you! (with my tongue firmly in my cheek!) So long as my family will be more comfortable on board and will want to come out again then it doesn't really matter if I'm saving 40 or 50% over mono-hullers, it's all a big improvement and better B.O.A.T anyway. (Balance Of All Things, Break Out Another Thousand, Broken Or About To!!) Will keep you posted on progress and tank test data. (which will probably cost more than the fuel saved by the next 5 hulls after mine!) Regards, John Winter