Ketch Rigged Catamaran
…excerpts from Chris White’s sailing report aboard his client’s Concept 63, ketch rigged catamaran design HERON
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Sunday, October 25, 1998, I joined Bill Shuman owner/builder of the new Concept 63 catamaran
HERON and crew Joan Welsh for a sail down the east coast of the USA.
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Immediately, I was struck by the way
Heron slides along at 10 knots in relatively light conditions. Our speed varied from 9 to 11 knots sailing close hauled in 12 to 14 knots of true wind speed with a rolling swell. During the first night the wind shifted to NE and fell away to near calm so we motorsailed into the next morning. Our first days run was about 230 n.miles.
As we neared Cape Hatteras the wind built stronger out of the northeast. For a while early on day two we had 25 knots of wind astern with waves of 6' to 8'. These waves were large enough to surf and we had a number of nice rides producing 16 to 18 knots of boat speed under full working sail. The Alpha autopilot did a fine job of steering but was not quite as good at catching waves as an attentive helmsman. In a ketch rig it pays to sail a very broad reach rather than a dead run since this prevents the mainsail from being blanketed from the mizzen. This we did and the sails were drawing well with only an occasional backwinding of the jib. The jib was snatch blocked to the rail giving a nice wide lead while main and mizzen each used a combination vang/preventer led to the leeward rail which provides the sail control of a 28' long traveler without the weight and expense.
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However, we had to jibe back to fetch Diamond Shoals 30 miles to our south but did so a little too early. After dark, with dinner in the oven, we strayed back into the Gulf Stream. The water temperature immediately shot up to 83 degrees! Over a period of 15 to 20 minutes the waves grew to 10' or so and steepened such that tops were falling over and the wind built to near gale force. Wow, that was quick! It was fun to let Heron strut her stuff for a little while, and strut she did with prolonged surfing rides generating 20 knots or more of speed. But it was also getting a little raucous below decks and with a full mizzen Heron was developing a lot of weather helm. We decided to get some sail off (double reef in the mizzen and rolled up about 20% of the jib) and jibe back to the SW to get out of the worst of the current
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Now that we were around the corner we were able to head more toward the west which brought the apparent wind up closer to the starboard beam. Heron loved this! With the wind direction NNE at 20 gusting to 25 we took off on a beam reach at a steady 14 knots occasionally reaching 17 in the puffs. The moon was bright, the wind now cold since it was coming off the land rather than the warm Gulf Stream and we were streaking along dry and comfortable with Cape Lookout 70 miles ahead but getting rapidly closer. But in the wee hours the wind once again fell away. Near Cape Lookout we finally gave up pure sailing for motorsailing at nearly 10 knots by running a single engine at 2300 rpm with light wind on the beam.
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Late in the day the breeze came around toward the SW and gradually built in strength. This was a great opportunity to see Heron sail upwind. We strapped the sheets in tight put both daggerboards down, set the autopilot and watched in awe as she powered up past 10 knots to 11.5 hard on the wind with full sail in about 18 knots of breeze. We had a wonderful fresh yellowfin tuna dinner in the main saloon watching the sun set while Bill's beautiful new machine devoured the miles toward Georgia. Under autopilot we were barreling along upwind enjoying our meal and spectacular view at the same time Joan's nearly full wine glass rested peacefully on the smooth table top without a ripple inside. Before dark I had a good chance to look at the masts for movement. With about 25+ knots apparent and full sail the rig was very stable. The masts were very straight and the leeward rigging still reasonably snug. A small amount of movement was seen in the mizzen masthead but this is to be expected with a long cantilever masthead. Most cats suffer from too much headstay sag which makes windward sailing less productive or requires a running backstay to remove. Heron has no running backstays but her rig is so efficient and stable due to the wide chainplate spacing and resulting large shroud angles that headstay sag is very minimal
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The NOAA forecasters had changed the predicted wind direction 4 times in the last 12 hours so the next wind was anybody's guess. My guess was that because the only wind direction that they had forgotten to predict was southeast, the wind was surely to arrive from that quadrant. Well, by mid afternoon we were having a beautiful sail with 12 knots of SE wind, beam reaching along toward the Sea Islands of Georgia where Bill and Joan planned to cruise a few days and I planned to depart.
As evening rolled into night we saw some of the nicest sailing that I have ever had the pleasure to enjoy. The moon was nearly full, the wind a gentle breeze from the port bow and the ocean absolutely flat. By now we were far enough south so that it was warm. I spent hours of my watch sitting in the trampoline near the windward bow watching the slender hulls slice cleanly through the water at a steady 8 to 9 knots
The wind, while very steady in direction became progressively lighter. By 3 am it was 7 knots by my best estimate (no wind speed instruments on board). It is always hard to evaluate performance of a new design without having a boat of known ability sailing alongside but these were ideal conditions to see how Heron sails to windward in light wind. By recording GPS and knotmeter speeds and headings over several minutes and averaging the readings I was able to get consistent results with little data scatter. We also tried several daggerboard settings and found that in this light wind it seems that Heron's best windward performance was obtained by having only one daggerboard fully down. Our best upwind VMG seemed to be at 5.93 knots boatspeed at an angle of about 53 degrees to the true wind. Pretty respectable for a conservative ketch rigged cruising cat in 7 knots of wind
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It was a great sail and very instructive for me. We saw a variety of conditions although the weather was generally light for the trip. Heron, with her long fine hulls, covers ground very well. I really like her rig, which although modest in size, is efficient and easy to handle. Going upwind in stronger conditions I had complete confidence in the spars which are extremely well supported by the long swept spreaders and efficient shroud angles. Light air performance was the big surprise. I knew that she'd be fast in a breeze but I did not fully appreciate how well she would sail in light air. This feature I ascribe to her more slender-than-normal hulls which are just so easy to move through the water.
Heron demonstrated that the catamaran Achilles' heel, underwing clearance and related pounding, could be dealt with successfully. We saw (actually felt) a few kicks to the belly in the sloppy conditions rounding Cape Hatteras but they were less frequent and less severe than most cruising cats that I've sailed. Sailing upwind in waves there would be a rumble of water noise every now and then as a wave top was mashed between the hull and wing intersection but it was easy to ignore. For her weight and overall beam the C-63 design has fairly generous underwing clearance. But it seems that the larger advantage is in her slender hulls which create much smaller (almost non-existent) bow waves. It seems to me that that hull waves are often responsible for a lot of the underwing slamming as they cause existing seas to peak upward at exactly the wrong time as the lowest part of the wing passes over them.
(BE noted: my observations as well)
Another issue of importance in a cruising cat is no wind, or very light wind. Racing boats are disqualified if they use the engine. Consequently boats designed to race (and the cruising boats that emulate the racing designs) have sail plans optimized for light air, which are often too large and too fragile for offshore cruising. Cruising boats, on the other hand, use the engine when the wind quits. And the time spent motoring, or motorsailing, is often quite significant. The term motorsailer has had negative connotations for decades. Normally motorsailers neither SAIL nor MOTOR very well. So they've been viewed with some disdain as neither fish nor fowl. But I view the Concept 63 design as a motorsailer that works. Her power performance with twin 50 HP diesels is quite good with 10 knots average speed at an easy 2750 rpm. Fuel consumption is very moderate and she achieves about 5 miles per gallon at 10 knots (typical for catamaran power boats is 3 mpg or less). But the real benefits happen when there is some wind too. Running one engine often is all that is needed to bring the apparent wind forward to make the sails work harder and the combination provides much better results than either motoring or sailing alone. And of course when there is wind you can shut off the noise makers and enjoy superb sailing at faster speeds than any reasonable engine could provide. I know that there is now considerable interest in power catamarans, with all the builders coming out with updated models. But honestly, there is nothing in the world quite as nice as shutting off the damn engines and SAILING.
In terms of weight or cost
Heron is no more boat than the typical 50' cruising cat, nor does she require any more effort to sail. But by drawing out the hulls to 63' in length substantial benefits are gained in performance and comfort. This combined with her 3' draft, the ability to pass under 65' bridges and excellent performance under power make her an incredibly versatile and pleasing cruising boat.
Chris White
Chris White Designs
Brian added: I agree wholeheartedly with all of the above !!!
Attached Files:
Aftmast rigs??? https://www.boatdesign.net/threads/aftmast-rigs.623/page-7#post-198607
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