Dear Mark, Your informant was quite correct as far as he goes. However our experience with the CS hull as applied to motor sailers shows that it is possible to apply a power boat hull form to a sailing catamaran to produce a boat with superior sailing and powering characteristics. We first used an early CS hull in 1983. This was on the Cordova.[see our web site under motor sailers] This boat motored at 18 knots and sailed on a reach at better than 20 knots [I had a photo of the sum log reading 24 knots!] It is the logitudinal rocker that the sail boat requires to enable it to tack and minimise transom drag that restricts its speed and leads to "squatting". The CS hull removes this rocker and results in a much less"displacement" of the water flow. Straighter water flow equals less resistance. The simplest way to counteract the diagonal downward thrust of the rig that your informant talks about is to move the rig further aft. The CS hull does have a fine half entry angle and would be prone to be effected by the height of the thrust of the rig[CE] so the hulls are made longer and the rigs moved further aft. The CS hulled motor sailer motors well and sails well. The only compromise is that they do not tack well, due to the straight keel line. This might be a problem on a round the buoys racer but is not too much of a problem on a long range ocean cruiser. Regards, Malcolm Tennant. MALCOLM TENNANT MULTIHULL DESIGN LTD PO Box 60513, Titirangi. Waitakere 0642 NEW ZEALAND Ph: +64 9 817 1988 e-mail: malcolm@tennantdesign.co.nz www.tennantdesign.co.nz www.catdesigners.com

I have been following this tread with some interest. I think that I should like to delve more deeper into Pat's comments here. Pat, give me an example of a sailcat (multihull or mono?) such as you mention below. One other point, would the diels be noisy, smelly? rupert,. On 16 Dec 2007, at 14:05, Pat Reischmann wrote: > Kites, diesel electric, retractable drive units? Why? The circle is > spiraling, > none of these alternatives are going to be able to cruise in the > teens or > twenties, so they are as I see it, sailcat alternatives. Why not > just go to a > sailcat? A well designed and built 45 ft sailcat, can motor at 10 > knots and > burn a couple of gallons an hour, and sail in the teens. Too hard? > Set it up > with a freestanding mast, a single electric winch to run everything, > self-tacking jib, and a nine year old child could sail it. Too > wide? shorten > the rig, narrow the beam and it will still blow away any kite rig. > Frankly > there is nothing more efficient on the water than a well designed > sailing cat > hull form. The cost difference of the diesel hybrid's that are out > there > Glacier, Solomon, compared to conventional small diesels and a > generator, > would pay for five or more years of diesel fuel, the systems are > complicated, > vunerable to lightning hits, and in most cases heavier, all the > while the > diesel engines are just getting better and better (common rail, > electronic) > etc. Worried about cost? Buy a used 40 ft. sailing cat for > 250-275k, don't > want to sail?, Pull the rig out of it, add slightly bigger diesels > (50-75 hp) > add a wedge or trim tab to the transom and cruise 10-12 knots and > burn three > gallons per hour. > _______________________________________________ > Power-Catamaran Mailing List