How to re-power and eventually rig a sloop into a ketch or yawl?

Discussion in 'Boat Design' started by Flody Boatwood, Aug 25, 2013.

  1. Flody Boatwood
    Joined: Aug 2013
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    Flody Boatwood New Member

    Salutations all!

    Having just read a fantastic and enlightening thread on a ketch vs yawl rig I decided to join the forum. I'm considering upgrading to a larger sailboat (32'). Upon further inspection the prior owner removed the 4cyl diesel inboard and the shaft (for whatever reason) patch and plugged it, and replaced it with a nice sized gas outboard off the transom.

    1) Any suggestions on re-powering (assuming I can find the parts to do it) with either a smaller 1cyl diesel engine and smaller prop...and or 5kw-10kw electric motor by it'self or as a gen-drive? (Basically what is the most cost effective way to chug this big beast around?)


    2) Since the cockpit has plenty of space and no dinghy davits in the way: Would any one suggest (or not) attempting to rig another smaller mast either on the transom or deck to make it a ketch/yawl? The current sloop rig just has a main and a jib (that i hope to make into a roller furler set up soon).

    Or should I just leave it all the way it is and save the time and money? I only hope to do some weekend coastal cruising with it to the Channel Islands someday soon, and to use it as a ocean camper to have some fun Transpac races for me with it.

    Cordially awaiting anyones thoughs, ideas, and suggestions!

  2. michael pierzga
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    michael pierzga Senior Member

    a 32 ft ketch is too small. All the rigging, boom mast steals people space in the cockpit. Stretch your 32 footer out to 65 ft the go ketch.

    As for power...nothing wrong with an outboard. A 5 horse that doubles as a dingy motor would be nice..

    I dont know much about electric feeling is that it is expensive
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    FAST FRED Senior Member

    (Basically what is the most cost effective way to chug this big beast around?)

    Diesel is nice but 90% of boats have gas engines with no hassles.

    I would find out what diameter prop was used , or what can be installed and if the diameter is large enough I would purchase a Honda gas engine with a 6-1 built in gearing. Used on rototillers . A large diameter 2 blade will be easy to line up with the deadwood .

    This will be economical to operate at light loads (unlike a diesel) and handle battery charge loads .

    NO you wont have reverse , but thats not a big deal since you KNOW in advance there is no reverse.
  4. viking north
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    viking north VINLAND

    You indicated a 4 cyl. diesel was removed. That usually indicates this is a heavy displacement boat, something in the order of 10,000 lbs. plus. From experience I have found a 3cyl. diesel, 25 to 30 hp. has no problem pushing a 10,000 lb. sailing hull to hull speed with reserve enough to punch thru reasonably heavy weather. Gasoline on board has always made me a little nervous and my experience with electric drives on two occasions has rendered them in my mind totally useless. Advise from this old builder would be : Bite the bullet and go for the inboard diesel. A low hour used 3 cyl. Yanmar,Volvo, Perkins, will be in the $2000 range and an additional $2000/$2500 should cover the remaining drive train including install.

    A yacht is not defined by the vessel but by the care and love of her owner ---
  5. Flody Boatwood
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    Flody Boatwood New Member

    Thank you Michael, Fred, and Viking for sharing your thoughts on this conundrum!

    -Yes having a nice outboard allready on a sturdy bracket dialed into the cables is a solid back up plan.

    Electric kits have been quoted to me at around $2k (not including the batteries). It sounds like the spinning shaft charges back up the battery while under sail power (which is kind of neat).

    -Yes I most certainly do have to find out what size and how long was the propellor and shaft that once was in it. 6:1 gear ratio sounds very appealing!

    -The vessel seems to be in the 16,000lb displacement/4,000lb ballast range and is very big/beamy (for me at least), and reverse would be very handy.

    Again, thank you for the advice and suggestions! This is going to be my biggsest boat project yet! = Lots of care and lots of love
  6. bpw
    Joined: May 2012
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    bpw Senior Member

    Use the outboard for a year or so before dropping 5 to 10 grand on a diesel. You might like it. Outboards are a lot easier to work on and don't take up space while making the interior hot and smelly. I just pulled the diesel out of my new 33 foot sailboat. Going to put a big double bunk where it used to be.

    Ketch rig will be more expensive and slower. Stick with the sloop. Maybe add a cutter stay.
  7. philSweet
    Joined: May 2008
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    philSweet Senior Member

    Outboards off the transom positively suck on boats over about 27 feet. Anything over a 2' chop and you are wizzing air even with a 25" shaft on an oversized mount. If it were just for a small lake or river, you might get away with it. But not in the ocean. Get a little three cylinder diesel and chug away. The old Kubota based jobs seem to be able to be rebuild forever. You might find an old Universal or Westerbeke at a decent price. And fit a little Martec folding prop - the cheap ones work fine (just two blades that fold on a pin).

    The other option, maybe , is a sail drive unit. Depends how you are set up.

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

    Outboards work, but work better on certain types of hulls. Boats that have much aft overhang will pluck the engine out pretty easily, so she'll die from over revving fairly quickly. If the LWL is right at the transom, you'll likely be fine, but if you have a counter, not so much.

    As to the conversion from a sloop to a ketch or yawl, well this is possible too, though a ketch will require a new rig and structure (steps, chainplates, etc.), while a yawl can likely keep the main in the sloop location, with it's chainplates (or most of them). A yawl rig is usually just a sloop, with a shortened boom and a mizzen stepped at the aft end of the cockpit. This allows you to retain good windward ability, yet offers a mule hoist for off wind work. You can split the backstay around the mizzen and have little other modifications to the main. The mizzen being proportionately smaller is lightly stayed too. This setup does clutter up the aft deck area, but well designed it can be less intrusive than you might think.

    It would be helpful to know what make, model and year boat you're contemplating this on.
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