Increasing Sail Area

Discussion in 'Sailboats' started by dm567, Jan 9, 2007.

  1. dm567
    Joined: Aug 2006
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    dm567 Junior Member

    I bought a motorsailer with more than adequate ballast. It has 10,600 lbs of ballast with a total displacement of 26,000. Yes a heavyweight. It is a ketch rigged Fisher 34. It has a capsize ration of 1.52 and a comfort ratio of 50, both good ratios. However, the SA/D is merely 11.5.

    There must be some way to increase the Sailing Area. What are the choices?

    DM
     
  2. Chris Ostlind

    Chris Ostlind Previous Member

    First thing... consult with the original designer and discuss your interest with them. He may have more current thoughts on the boat.

    That being a problem... find another good designer with experience in motorsailing craft and invest in their expertise.

    Chris Ostlind
     
  3. dm567
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    dm567 Junior Member

    I do have an email to Northshore Yachts but as of now they have not responded. If I were buying a new one I'm sure they would have by now.

    I don't expect the Fisher to be a raceboat and it is what it is. However, having acknowledged that, there may be interesting ways to help it perform better even if the increase in performance is marginal.

    I was thinking of potential changes myself because this is a hobby, not a business and part of the fun will be to experiment and communicate with others. Hiring a professional is an option but I think this and other forums have the expertise to make valuable suggestions.

    The changes I have thought of:

    1. Increasing the height of both masts

    2. Adding a Hoyt self tacking boom and making the jib self tacking and then adding an additional furler for a cruising spinniker in front of the stay, the furthr forward the better.

    I like the idea of the self tacking jib when motorsailing and when the wind is right using the spinniker.

    Any thoughts?

    BTW I posted here instead of the motorsailing section because I wanted sailor's opinions. There must be some sailers that have modified the OEM sail area with success.

    DM
     
  4. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    The fisher 34 has some hull form issues that preclude it being a particularly good sailer, likely why they've elected to keep the SA/D low. She's got her displacement carried well toward the ends of the boat, which makes for a nice motion and lots of interior space, but not the greatest wave train (she drags along a pretty substantial "hole" with her, underway). Her dramatic, yet stylishly tucked up buttocks will kill any real windward potential, frankly needing the engine to get to weather, which is as a true motorsailor should be.

    You could increase the area on this boat, but her potential will not improve much. She should make hull speed with the current rig in moderate winds. Light air potential could be improved (as any boat can) with a kite or additional area. A significantly taller rig will probably move chain plate locations, possibly mizzen placement and place much increased loads on the existing hard points (steps, compression posts, bulkheads, chain plates, etc.). This may require a general up sizing of all the rigging components (blocks, tangs, spars, etc.) to accommodate the additional loads. Coupled with the relatively high CG (iron ballast, tall deck structures, etc.) it would be wise to consult with Northshore or skilled designer.
     
  5. dm567
    Joined: Aug 2006
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    dm567 Junior Member

    PAR,

    Thank you for the response. I don't think a taller rig would make any sense.

    What do you specifically think of:
    "Adding a Hoyt self tacking boom and making the jib self tacking and then adding an additional furler for a cruising spinniker in front of the stay."

    http://www.sailcdi.com/Spinnakerfurler.htm

    DM
     
  6. rayk
    Joined: Nov 2006
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    rayk Senior Member

    dm567,

    How about the Hoyt self tacker and a gennaker to hoist?
    Bit less gear, and simpler too?
     

  7. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    I think switching from a genoa to a self tending jib (whatever style) will reduce performance, from the lose of area and slot effect on the main. A cruising spinnaker, possibly on a double head stay is a good idea, though a furler is additional money and complication where you aren't likely to need it (at least on a chute). Typically the weather is pretty nice when you're thinking about a spinnaker hoist on a motorsailor. I personally like the idea of good furler/reefing drums on the big genoa, when you need the power and ability to reduce area, rather then handing headsails on a pitching, slippery, confined foredeck, in building winds. I'd also consider adding a mizzen mule (staysail) to increase light air ability. They provide a lot of power to the ketch rig with the wind abeam or farther aft. Adding roach and full battens to the main will increase area, performance and control, though your split backs may need relocating a bit (maybe not). Honestly, you'll do well to maintain 7 knots under sail, with that hull form and rig, which is a very respectable for her, and the perfect speed for sight seeing. 7 and a half knots would be flying all she can carry and white knuckles at the helm. More often then not you're doing mid 6's and grateful. I mean no disrespect, she's a tough, well built craft and is what she is, a well burdened motorsailor. She has style, grace and comfort, plus is reasonable economical to operate.
     
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