Cat ketch trimaran

Discussion in 'Multihulls' started by peterbike, May 23, 2018.

  1. peterbike
    Joined: Dec 2017
    Posts: 21
    Likes: 2, Points: 3
    Location: melbourne

    peterbike Junior Member

    The concept has been rattling round in my head for years, but I have found little to nothing regarding them. I know there are/were 2.
    1. is the chris white design for sale in america somewhere.
    2. One is mentioned in the historical thread (if I read correctly ?) about 1 in australian race where it got a slow start, then took off & passed everything in sight. ( anyone know it ?)

    Gary's little cox bay skimmer, which proves that the mast's don't have to be free standing.
    Although it is a nice idea, after reading about Rob Denneys sail handling on the prau - the thought becomes, " I want one of those !"
    The idea of 2 smaller packages is appealing. - although it has occured to me as I sit here typing,
    "Is this a relevant idea anymore ?"
    Have roller furlers done away with this fear of big flappy things trying to hurt you ?

    I still think the idea has merit - even if only from the standpoint, "if one falls down, there is still another one" ;)
     
  2. Tiny Turnip
    Joined: Mar 2008
    Posts: 564
    Likes: 63, Points: 28, Legacy Rep: 743
    Location: Huddersfield, UK

    Tiny Turnip Senior Member

    Like this?
     
  3. Gary Baigent
    Joined: Jul 2005
    Posts: 2,924
    Likes: 80, Points: 48, Legacy Rep: 509
    Location: auckland nz

    Gary Baigent Senior Member

    From Light Brigade:
    Then in the mid 1970s Young designed Dooley Wilson a 40 foot open wing deck trimaran named Bladon Racer; called a sketch for it was neither ketch nor schooner because both masts and mainsails were the same height and carried the same sail area in two roached, fully battened mainsails. “This was a low sail plan which kept the centre of effort down and reduced the tipping moment,” said Young. Although Young drew water ballast to be carried in the windward float to provide extra power, this was not fitted by Wilson. In the clever drawing, tanks which were linked to the centre board cases, could fill or empty to produce either buoyancy or lever arm weight. The whole object was to get as much sail on the boat as possible without much height. Matched with a bigger rig she would have been very fast indeed. Bladon Racer had a centreboard in each float which saved space in the main hull.
     

    Attached Files:

    dsigned likes this.
  4. peterbike
    Joined: Dec 2017
    Posts: 21
    Likes: 2, Points: 3
    Location: melbourne

    peterbike Junior Member

    Tiny T - not quite, nice try tho.. :oops:
    Gary, that boat must have been pretty radical for the period. A bit like us looking at mod 70's now ?
    I have given this some serious thought since the original posting. Times & technology have changed, ketch's are a thing of the past pretty much.
    And it is true for ultimate speed, the taller the mast the better . So for racers, it's a no-no. (unless they choose to race only, when there is a bit of breeze around. o_O)
    I like multihulls becos they are efficient, dragging a coupla ton of lead around & parking 3 mile away from the beach - cos your boat is 8' deep - is not efficient. When the freedom 40's turned up in the late '70's with the catch phrase, "mon on de sea, you got to be free" they really caught my attention.
    But I was 18 & could not afford (or understand) carbon fibre masts. So I sailed my steel mono pig around for a little bit, before swapping it for a slim steel mono thing. But the writing was on the wall - one day I was going to get an efficient boat.
    So the cat ketch falls into the 'efficient' category, not ultimately fast - but with a good turn of speed.
    It might still be a little bit early for the early for 'cat ketch's' as the mast/s are still a problem re. getting a clean leading edge that is acceptable to the masses. But that could change, with the AC boys playing with twin sail tracks & the like.
    I don't have a problem with a jib, but the rear mast is still a concern. Wing mast's ? FANTASTIC !... if it can be proved that will remain docile & well behaved at all times ...???
    here's a photo of another lunatic fringer I found in another thread ; https://www.boatdesign.net/attachments/greg-elliot-jpg.52028/
    Another idea i had is to treat the rear sail like a gennaker/spinnaker, in that it is only used in light airs. So that at 10/12 knots you drop it completely - first reef done. : If so, could the sailcloth be lighter & same for the mast construction ? - reduced guilt about dragging extra weight around ?
    Of course this would upset the balance of the boat, so another centreboard in the cockpit for use when the mizzen is up & blanked off when sail comes down.
    My 3c for today, ciao
     
  5. peterbike
    Joined: Dec 2017
    Posts: 21
    Likes: 2, Points: 3
    Location: melbourne

    peterbike Junior Member

  6. rob denney
    Joined: Feb 2005
    Posts: 684
    Likes: 52, Points: 28, Legacy Rep: 436
    Location: Australia

    rob denney Senior Member

    Glad you like the boats.
    $300,000 was the estimated (yet to be confirmed) cost for a 60'ter. CRUISER 60 – Harryproa http://harryproa.com/?p=1747

    A cat that length designed by Chris White would cost ~10 times as much. A Gunboat, ~15 times. And neither would be as easy to sail or as fast. Why the difference?
    Simpler boat and rig. No daggerboards, standing rigging or extra sails and the gear they require.
    No advertising budget
    No middlemen
    No need for carbon everything to make it sound glitzy
    1 engine and solar panels vs 2 engines and gen set
    Less boat, so less materials and less space to fill with stuff that is rarely used (eg the 4th double stateroom). 5 tonnes vs 12 vs 16.
    Simpler to build due to Intelligent Infusion INTELLIGENT INFUSION – Harryproa http://harryproa.com/?p=1845

    You could have a 40 or 50'ter built for considerably less. And less again if you were to be involved in the building process, which gives the added advantage of knowing exactly what is in the boat and how it all works.

    If you are interested in a second hand one, email me at harryproa@gmail.com.

    If a keel "is not efficient as it has to be dragged around all the time", then the same applies to the windward hull of a trimaran, most of the windward bow of a cat and all the extra sails and their gear and beefing up they require. The same could be said for the twin deisels, tanks, props and saildrives vs a single large outboard on the tender approach on the harryproa. If efficiency is judged by every part of the boat doing it's job as much of the time as possible, then a harryproa is the most efficient type, by far.
     
    rwatson likes this.
  7. brian eiland
    Joined: Jun 2002
    Posts: 4,776
    Likes: 150, Points: 73, Legacy Rep: 1903
    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

  8. brian eiland
    Joined: Jun 2002
    Posts: 4,776
    Likes: 150, Points: 73, Legacy Rep: 1903
    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    Ketch Rigged Catamaran

    …excerpts from Chris White’s sailing report aboard his client’s Concept 63, ketch rigged catamaran design HERON
    _________________________________________________________________
    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.

    ……text break…..

    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.

    ……text break….

    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

    ……text break….

    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.

    ……text break….

    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

    …….text break

    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

    ……text break….

    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
     
  9. peterbike
    Joined: Dec 2017
    Posts: 21
    Likes: 2, Points: 3
    Location: melbourne

    peterbike Junior Member

    Rob, it is the 50' cruiser that I am interested in - possibly none to buy second hand ?
    What about materials cost ? 10% less than the 60 ?
    Builder - me & a couple of youngsters.
    but i am not ready to go yet, I have to finish renovating this house & sell it. (patience grasshopper, I says)
     
  10. rob denney
    Joined: Feb 2005
    Posts: 684
    Likes: 52, Points: 28, Legacy Rep: 436
    Location: Australia

    rob denney Senior Member

    Send me an email, please.
    Closer to 20%.
    They/you will have a ball, especially if you have spent time hand laminating, fairing or cutting and fitting floors and bulkheads on a conventional build.
    No rush. Let me know when you are ready to go.
     
  11. peterbike
    Joined: Dec 2017
    Posts: 21
    Likes: 2, Points: 3
    Location: melbourne

    peterbike Junior Member

    Another looney !
     
  12. brian eiland
    Joined: Jun 2002
    Posts: 4,776
    Likes: 150, Points: 73, Legacy Rep: 1903
    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    What is so looney about that as cruising rig??
     

  13. Gary Baigent
    Joined: Jul 2005
    Posts: 2,924
    Likes: 80, Points: 48, Legacy Rep: 509
    Location: auckland nz

    Gary Baigent Senior Member

    Schooner rig on a reach is very, very fast. And if masts rotate and are airfoil shaped, surprisingly fast and embarrassingly high pointing to windward too. Obvious ****? But not to bigots.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.