Mark wrote: showing that one needs to think creatively about lifecycle costs, your approach of making a "38' boat" on 50' hulls certainly seems to make a lot of sense. As others have pointed out, the systems and interior are a large factor of the expense, it should certainly be less expensive than a normally proportioned 50' design. Brian replied: A lot of multihull designs have advocated this for years, but invariably the owner finds a reason to fill up the 'ends' of the vessel, thus overweight and possible dangerous. ________________________________________ Mark wrote: > I'd also like to hear more about the centerline diesel. I've often wondered if one could do a larger dia, lower rpm, single prop between the hulls would be only a modest or in fact a significant efficiency gain (not sure if that's what you are doing). As a detail question, when using small outboards for menauvering on such a large boat, how do you get an appropriate prop on them to get some bit and not just slip like crazy? Brian replied: Ive suggested this arrangement on some sailing cats, "If I were looking to use my auxiliary engine in a strictly aux manner, rather than in a motor/sailing demand, I would seriously consider a single engine installation. This engine would be conveniently mounted in an enclosure on the cockpit deck and would belt drive a steerable out-drive leg that would be incorporated into the rear portion of the central nacelle structure. Maybe this rear nacelle might appear as on "Earthling's pod" (attached photo and/or <www.earthling.co.nz/boating.htm> This saves the cost and weight of the second engine, trans, shafting, prop, etc, and opens up the rears of the hulls for a nice master bath, or whatever." On a power cat this begins to look real feasible with the use of a single diesel/electric power source and an azimthing propeller unit like this, <http://boatdesign.net/forums/showpost.php?p=79625&postcount=9> Why carry 3 motors of 2 different fuel types. And yes I don't want to try and maneuver in a tight spot, or with any significant wind utilizing two small seperate outboards....could be an expensive repair bill to my neighbor's boat. Brian Eiland beiland@usa.net www.RunningTideYachts.com distinctive expedition yachts