Cat Ketch or Cat Schooner Rig on Trimaran...

Discussion in 'Multihulls' started by tropostudio, Jan 27, 2023.

  1. tropostudio
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    tropostudio Senior Member

    The little one finds about efficacy of cat ketch rigs on multis- trimarans in particular- seems to point toward better performance with the aft sail and mast removed. Newick White' Wings is the example that first comes to mind, as not tacking well with the aft rig. My recollection of source is foggy, but I recall something about a rig that worked fine on a traditional mono didn't work out on a tri. Can someone shed more light on this? Is it a matter of balance between sails combined CE and appendage CE, along with momentum through a tack? Can't figure why it would be intrinsically bad on mutlti vs a mono. Let's disregard structural and staying issues for masts and rigs if we can...
     
  2. oldmulti
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    oldmulti Senior Member

    tropostudio. Any rig if correctly designed will work on a multi as well as mono. The only issue is how fast the multi can go. Cruising catamarans or trimarans that sails at EG 60% of wind speed can run a ketch or schooner rig just as well as a mono. The only variation is the sails may need to be cut slightly flatter.
    If the multihull is a high performance machine that can sail faster than wind speed then there is more emphasis on fine reaching upwind work which requires a more efficient rig and generally that means a sloop or fractional single mast rig. (These are generalizations but the logic is basically sound).
    As usual there are exceptions. Very large multihulls can be fast and have multimast rigs for ease of sail handling etc and there are several racing multihulls that had schooner rigs that could go to windward very well. Also James Wharram claimed his Pahi 63 could go very well to windward with there schooner rigs.

    Of the confirmed fast multihulls with schooner rigs the few examples are Shotover and Jarcat 23 that raced successfully in Australia, Spronk cats that sail well in the Caribbean, The Nigel Irens (racing tri designer) designed 64 foot cat, many HarryProa's. This is just a few of some fast multimast multihulls. Have fun in your search.
     

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  3. tropostudio
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    tropostudio Senior Member

    Thanks, oldmulti. I sort of assumed there as nothing inherent in a light tri vs a mono with ballast that would make it not tack well. I presume if White Wings performed better with the mizzen removed, then a poor design decision had been made originally.
     
  4. cavalier mk2
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    cavalier mk2 Senior Member

    I never heard White Wings had trouble tacking, there were delivery reviews in Multihulls Mag or Woodenboat. There was one up in the PNW that had cruised around Vancouver Island and that takes lots of tacking up the inside. They kept the mizzen.
    Dick used a similar rig on his smaller Rozinate? design, a 29 footer. The challenge they had was cutting the main to get a good shape with the unstayed mast. Check your sources, I'd be interested in hearing more about them. I've saw the one built in Oregon up here and it was a nice boat. Sometimes these craft wind up with new owners who aren't really sailors.
     
  5. Tiny Turnip
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    Tiny Turnip Senior Member

    Fwiw my (very) little ketch rigged tri very clearly benefits from the mizzen for power, handling and tacking.
     

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  6. tropostudio
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    tropostudio Senior Member

    Cavalier -

    Not regarding tacking per se, but about mizzen flow and mast tension issues:
    Multihull Structure Thoughts https://www.boatdesign.net/threads/multihull-structure-thoughts.62361/page-58. Posted by jamez on this forum. It references this conversation on SA:

    It references this conversation on SA:
    Is it just me, or is every Newick ever built as ugly as sin? https://forums.sailinganarchy.com/threads/is-it-just-me-or-is-every-newick-ever-built-as-ugly-as-sin.205080/page-7
    Comments were by a White Wings owner who sounds like a sailor.
     
  7. tropostudio
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    tropostudio Senior Member

    Above items were regarding a White Wings.

    Here is a review regarding Damfino :
    <Like all prototypes, Damfino has had to face her compromises and teething aches. He’s had to tune the stiffness of the vertical carbon battens on the main. Cutting and setting sails to accept what can become several feet of bend in the unstayed mast also is an art. Conlin acknowledges that you really don’t want to be caught having to short tack out a channel, because the boat needs to get up to speed to come around. The flat mizzen can help stall a tack by pushing the boat back into the wind, so Conlin has learned to sometimes ease it off. The amas also sit 2 inches lower than designed, says Conlin. On a racing machine, if the boat could remain perfectly balanced at rest, the amas would both hover well above the water. In reality, the racer leans over on one side, then flops over as the boat sways about, a discomfort for cruisers but essential when tacking an extremely wide boat so that it doesn’t have to drag its long leeward ama around in a big arc before the ama lifts and allows the boat to come off on the new board. Damfino‘s amas steady her at anchor, but Conlin plans to raise them on future boats to aid tacking.>

    Full article here:
    Responsive Damfino is a classic Newick tri - Ocean Navigator https://oceannavigator.com/responsive-damfino-is-a-classic-newick-tri/
     
  8. cavalier mk2
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    cavalier mk2 Senior Member

    It all sounds like a rerig design error to a square top and of course operator error to me. Yes, a mizzen can need to be eased when tacking, they are also handy for heaving to etc...
    So I think I'll stick with my sailor assessment.
     
  9. oldmulti
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    oldmulti Senior Member

    This is from Ron Badly the owner of White Wings commenting on mast rotation but it also describes other things about the rig. I have not edited it. Page 149 Multihull Structure Thoughts.
    "The rotation system is quite simple. The is a Derilin cup at the base of the mast captured by an outer stainless cup. The base of the mast is coated in graphite. At the deck there is a plastic needle bearing set up with rings to retain everything. I have the mast out of the boat right now and will get some pictures of the parts later. I was thinking of changing the rig to a regular 3 point stayed arrangement but have changed my mind on that.

    About 10 years ago we were on our way to a multihull sail-in. It was quite windy when we set out, over 20 knots. When the wind freshened even more we decided to turn back as the sail-in was about 25 miles straight up wind. The mast rotation was controlled by an electric motor with a chain ring around the mast. This made it really easy to roll up the sail but wouldn’t hold it in position for reefing. That’s not really an issue as a reef was very seldom required in our light wind area of British Columbia.

    So, we are now sailing downwind under full main and mizzen in probably about 30 knots of wind. Drifter is under control and moving along very well. We were probably doing between 12 and 15 knots. There was a land mass ahead and we needed to jibe. The original sail was the two ply Ljungstrom held together at the clews by a clumsy shackle arrangement. Halfway through the jibe the sail opened up from the clews, we now had nearly double the sail area and my goodness did we take off! My wife isn’t an experienced sailer but even she was aware of things going wrong. I was too busy steering to look at the speedo but we must have been doing well over 20 knots. We stuffed all 3 bows into the back side of a steep wave. I was reaching for the radio because I was sure we were looking at a pitchpole in progress.

    The bow of the main hull is quite flared and the floats are very rounded. The flare saved us, I’m sure. Lots of buoyancy up there. I was able to bring the boat through the jibe after riding over the wave and then rolled up the sail completely. We finished our little trip under mizzen only. I called Dick later and thanked him for his good design sense.

    Once back at the dock I took the main off and ordered a “normal” square top sail with reef points. This was with Dicks permission. Drifter has since been altered to a wishbone boom and the mizzen is gone. There are more modifications but I’ll save those for another day. Overall the boat is a pleasure to sail and very comfortable. It points as high as anything out there but could use more power. Hence the thoughts on changing the rig. I think I’ll just get a bigger main and make a longer wishbone."
     
  10. tropostudio
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    tropostudio Senior Member

    Thanks, oldmulti - missed that one on your 'multi structural thought' thread.

    Cavalier -the link to the Damfino review is worth a look. The quirks of the flat mizzen and bringing a light, wide boat through a tack make total sense. Sounds not much different than roll-tacking a dinghy to get it through the wind.
     
  11. cavalier mk2
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    cavalier mk2 Senior Member

    The balance for a rolled around the mast main is important. The builder changed some things for his local conditions and convenience. The original specs are for a winch operating the mast which gives you the nonslip reefing when cleated. A ratcheting winch for the electric conversion might work... Having the leeches of the Lungstrum main secured is important in a breeze as the owner discovered.
    The original rig did feature a loose luff drifter/jib for light air days. His conventional reefing square top does solve the fore/aft balance when shortening sail but that puts the area up higher which I'm not a fan of for cruising. Each to their own...
     
  12. tropostudio
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    tropostudio Senior Member

    Cavalier - I follow. Rig changes are easier than reworking board and rudder configurations, but changes in one affect the other. Balance.
     
    Last edited: Jan 29, 2023
  13. cavalier mk2
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    cavalier mk2 Senior Member


  14. tropostudio
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    tropostudio Senior Member

    Apologies, cavalier. Mixing names from other multihull threads!
     
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