I'm aware that surgeons often view many of their patients' problems as best treated with surgery . . . while the acupuncturist is likely to view many of his patients' problems as best treated with "needles/pins." With this in mind, be aware that I'm a catamaran dealer, and thus . . . well, you see where this is heading. However, anecdotal evidence is sometimes STILL valid and quantifiable. As such, we had a client who'd purchased a 47' (x 18' x 3') power cat (twin Cat diesels: 15 knot cruising, 21 knot max.), which he had shipped from it's yard-of-origin in New Zealand to San Diego. The owner then planned to motor it north to its new home in Seattle. AS it happened, he hooked up with two monohull trawlers (a Grand Banks and a Nordhavn, each about 40'), also headed for the Puget Sound region. Although the monohulls cruise at barely half the pace that the cat can, the cat owner liked the notion of "safety in numbers" and the three yachts decided to travel together. The first 2 days were mild, but then conditions deteriorated: winds up to 14-to-17 knots from the northwest, and rising seas. Do-able while heading north, but not ideal. Within about 24 hours one of the monohulls lost its stabilizing system, so all three yachts headed for shore. Repairs were made and they were underway inless than 3 days. Not less than another 24 hours passed before the stabilizing system on the other monohull proved problematic. Again they headed to shore. The cat owner told me that when the stabilizing systems gave out on each boat, he was amazed to see how badly they rolled and moved about. He couldn't quite imagine, he told me, HOW their crews could do much of anythign onboard with so much motion going on. The repairs for the second boat could not be readily made, so the cat owner decided to head off on his own. The weather had deteriorated even a bit more. For more than a day he was taking white water over his flybridge . . . but, as with most cats, he also found that despite the comfort afforded by the built-in stability of two, widely-spaced hulls at lower speeds, there was the added benefit (known to all cat users, whether their cats are 10' or 70' in length), that as the water gets rougher, adding speed (completely unlike with a monohull), gives an increasingly MORE comfortable ride because -- starting at about 11 or 12 knots -- a "cushion of air/foam" begins to develop between the hulls. I've experienced this running from FL. to the Bahamas. As anyone who has run the Gulf Stream there knows, when the wind clocks around (about every 7-to-10 days), and blows from the north, directly against the northward moving stream, the seas build up into blocks -- not waves as we normally know them, but blocks (flat-sided "hunks" of water from which boats "fall off of" for distances of 4 to 6 feet or more). Frankly, I was plain frightened when a skilled cat captain took me out in those conditions and launched us off some of the "blocks." It initially seemed crazy to me that he'd INCREASE the catamaran's speed in these flat side blocks of water. And yet, very quickly I discovered this "built-in cushioning effect," afforded by the tunnel -- the cat's hulls and the bridgedeck (horizontal platform between the two hulls) -- that pockets this air/foam and creates the cushion. Monohulls, as it gets rougher, you slow down. Counter-intuitively, when things start to get roughter, cats improve by adding some speed. Weird, huh? Anyway, the 47' New Zealand cat found that in the relatively rough conditions, his boat was MOST comfortable at about 12-14 knots. And so, he soon found port in Seattle. The two trawlers straggled in more than a week later, having pushed as well as they could in conditions that kept them to 5 to 6 knots. Again, you can say this is anecdotal, and I wouldn't argue with you. But there is a REASON that power cats are so common in New Zealand and Australia. In the U.S., boaters typically don't go out if the conditions are close to small-craft warnings. If that were the limiting factor in parts of N.Z. and Australia and the "vigorous" surrounding Southern Ocean, there wouldn't be much boating there, period. (I won't mention the "leading brands" of popular U.S. monohulls that have flat-out failed, sales wise, down there -- DESPITE the benefit of the weak U.S. dollar -- because the boats simply couldn't stand up to the conditions that are so common there. Instead, Kiwi and Aussie boaters frequently select the built-in stability, and rough-water capability of twin hulls. And that's a primary reason why you'll see 8 to 10 times MORE cats there than in U.S. marinas. I'm glad that stabilizer systems allow more boaters to get out on the water in greater comfort. But the problems that can occur with stabilizers -- and the frequency with which they do -- goes beyond anecdotal occasions. So I'm just adding this note that there are other designs which, well . . . don't even need 'em. (Okay...let the bricks fly! grin) Regards, Rod Gibbons Cruising Cats USA -----Original Message----- >From: "Scott E. Bulger" <scottebulger@comcast.net> >Sent: Jun 21, 2007 10:38 AM >To: 'Passagemaking Under Power List' <passagemaking-under-power@lists.samurai.com> >Subject: Re: [PUP] In praise of paravanes > >The only thing I'd add to John's comments is that no news is good news >regarding active fins. I do believe there are hundreds, perhaps thousands >of boats with active fins that are motoring around just fine. I had >Alanui's system checked out by the local TRAC representative last week. He >showed me two areas where some chafing of the hydraulic lines was occurring >and advised installing a simple sheath to prevent further erosion. I was >prompted to have this inspection by Jeff Merrill of Nordhavn, as a prudent >thing to do prior to leaving for a two year cruise. The systems review the >rep provided was great, a wealth of information. Simply put, the system is >in great condition and I'm confident it's as ready for the voyage as any >other component in the boat. I was considering adding paravanes, but since >I've modified our itinerary to a near coastal route I'm going to forego >them, since I should be able to have parts sent to me in the event we >experience a failure. > >In summary, we should realize our sample of experience on the list is very >narrow and doesn't reflect a large enough cross section of the industry to >reach comprehensive conclusions. It is valuable non the less, as each of >these experiences does provide a great learning environment for all the >participants. > >Thanks to all those that share their valued opinions and observations! > >Scott Bulger, Alanui, N40II, Seattle WA