Canoe to schooner conversion

Discussion in 'Sailboats' started by rcnesneg, Jan 15, 2015.

  1. rcnesneg
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    rcnesneg Senior Member

    I see. I'll have to do a lot more research into it obviously, especially with stability as the primary concern. Thank you for the information.
     
  2. sharpii2
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    sharpii2 Senior Member

    I did some envelope doodling.

    I came up with a relatively evocative schooner rig, complete with a tiny jib.

    The Main Mast ended up being 10.5 feet tall, and the Fore mast ended up being 8.5 ft tall.

    The Main Boom ended up being 6.0 ft long and its gaff ended up just 4.0 feet long.

    The Fore Boom was just 4.5 ft long, with a 3.0 ft gaff.

    The Jib has a 7.0 ft hoist and a 4.5 ft foot. It is set on a tethered Boom, so the Fore Mast doesn't need shrouds or stays.

    The Area breakdown came to this:

    Main Sail:--35.0 sf
    Fore Sail:--19.6 sf
    Jib:---------15.7 sf

    This gives a total Sail Area of 70.3 sf.

    Sorry, no pictures.

    Both Main and Fore Sail would have a hoist that equals their Boom Length.

    The Vertical Center of Area (VCA) of this rig would be about 5.25 ft from the bottom of the canoe. You would be expected to sit there, on a boat cushion perhaps. The Booms would clear the bottom of the canoe by 2.5 ft, requiring only modest head ducking

    With just you aboard, it should be quite fast, at least reaching and off the wind. With two on board, its performance should still be quite respectable, with no gymnastics needed to keep it on its feet.

    It would win no prizes for windward performance, though, but such should be at least adequate

    Reefing would be an all-or-nothing affair. Each sail would either be fully hoisted or fully lowered. Lazy jacks would catch both the Fore Sail and the Main Sail. The jib would be raised with a remote halyard, and lowered with a remote down haul.

    First reef would be dropping the Fore Sail. Second reef would be dropping the Jib and Main, then raising the Fore Sail.

    This should balance at least reasonably well with the two combinations mentioned.

    With reasonably well designed bridles for the gaffs, you may be able to get away with just three halyards.

    Such a rig would still keep you really busy, with three sheet lines and a tiller to manage.

    But it would be a real conversation starter, particularly if it could be made to work well.
     
  3. rcnesneg
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    rcnesneg Senior Member

    I drew up what you designed, but I added a main gaff tops'l and a flying jib. I like the short masts a lot better, the sail area still looks pretty good on the hull size for light wind. I don't like the strange looking foresail though with the foot so high.

    [​IMG]
     
  4. JosephT
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    JosephT Senior Member

    Agree with PAR, too much sail area and the hull needs some work. Keep in mind most small monohull sailboats tend to heel over a bit, and the port/starboard sides of the hull spend much of their time acting as independent hulls.

    Since you have a canoe hull, you're probably better off rigging it as a sailing canoe. The sail area is much smaller (lateen rig) and an attached lee board. Lots of plans out there for sailing canoes and that may be a more realistic objective.

    Good web site here showing some typical conversions.

    http://www.ocsg.org.uk/

    If you're intent on hitting big water (e.g. open ocean vs. enclosed bay) you're better off having a look at some true sailboat designs (e.g. Laser, Sunfish, Hobie Cat, etc.). Many to choose from and there are plans for home built designs. If you're intent on designing a good boat, base it off a similar model and make improvements that don't sacrifice seaworthiness.
     
  5. rcnesneg
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    rcnesneg Senior Member

    I'm looking for what to do with an old canoe that is interesting and fun, and maybe a little bit funny. I have a Prindle 16, a 16' homebuilt trimaran, 8' homebuilt mini yacht, and access to Sunfish, a Hobie Fox (Formula 20), Hobie 16, Catalina 22 and 27, and Oday 22.

    I drew up a bit more on the schooner plan with the flying jib and tops'l removed. I don't like it to be honest. I feel it loses it's schooner character. I also switched out the foils to a daggerboard and separate rudder. I don't like the daggerboard placement.. I might consider an off-center single daggerboard(like leeboard but hidden inside the boat and a daggerboard instead of hinged like a leeboard) so I can still sit in the middle.

    [​IMG]
     
  6. sharpii2
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    sharpii2 Senior Member

    Hi rcnsneg.

    Attached is a schematic drawing of the schooner rig I described yesterday.

    I was a little optimistic about the Sail Area. Actually it would probably end up being closer to 65 sf.

    The 7.0 ft tall jib had to be shortened to 6.5 ft and no allowance was made for spar thicknesses.

    Still, I think it could be made quite manageable with no outside ballast, and no hiking boards or trapezes, as the Center of Area (CA) of the combined rig is quite low.

    With the keel you have drawn, the boat would have to be launched from a boat ramp and kept at a dock.

    Also, with a ballasted keel, sinking is a real possibility, if the boat is ever capsized. This of course can be mitigated by having closed off compartments in the bow and stern, which have enough buoyancy to overcome the weight of the ballast.

    just thinking aloud.
     

    Attached Files:

  7. rcnesneg
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    rcnesneg Senior Member

    That's a very good point. It already has sealed foam in the last foot of the bow and stern, so I suspect around 30 lbs of buoyancy. I wasn't planning on using ballast on it, but if I did, it would probably be borrowing the 50 lb weighted daggerboard from my pocket yacht. If that was the case, I definitely need to add more foam. The pocket yacht has about 250 lbs of flotation, fully swamped.

    Thanks for drawing up the plan. It looks well thought out. I would drop the boom on the mainsail as low as I could, there's no reason for having it up high, it doesn't have to clear anything except the stern of the boat. I like having a boom on the foresail even though it means less clearance and more likelihood of bumping my head. Having everything self-tending is very nice, and should make tacking so much better, easier than most sailboats I sail that have separate jib sheets and require attention when tacking. I don't see any harm in adding a main gaff topsail, it improves performance to windward, adds very little weight, and requires no extra attention. I really like having the bowsprit and flying jib, even if I only use two headsails instead of three. It adds a lot of character. I suspect I would end up only using two headsails when on long tacks, not while maneuvering. It's very easy to pull them back into the cockpit if needed.

    I really feel that most of the purpose of this boat is being lost in the attempt to make it perform better and be more like traditional sailing canoes. It is more of a funny clown boat(in a classic wooden boat way) to mess around in than anything else.

    Perhaps I should redefine some goals.
    Qualitative: 1. Looks (like a classic schooner) 2. Safety 3.comfort/ease of handling and setup/takedown.

    Quantitative: 1. Single-handed, room for one passenger. 2.Able to sail off a lee shore with some reserve in pointing. 3.Retain cartoppability as with plain canoe.

    That's about it.
     
  8. sharpii2
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    sharpii2 Senior Member

    See comments in text.
     
  9. rcnesneg
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    rcnesneg Senior Member

    I would worry about sitting behind the main mast, as that little area has very little buoyancy and it gets very tippy as you go up and toward the ends.

    This is a picture of the hull and it's internal structure before I finished it. It basically remains unchanged. I intend to keep all occupants in the center section between bulkheads. The yoke in the center is going to go away. There really isn't room on the ends for anything other than two backpacks or something like that.

    [​IMG]
     
  10. gonzo
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    gonzo Senior Member

    You should consider the torsion of the rig on the hull. A canoe with no deck has little structural strength in that direction. Sailing canoes usually have at least narrow side decks.
     
  11. TANSL
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    TANSL Senior Member

    How is it possible that the rig produce torques on the hull?. I am not able to see it. I would not worry about this.
    The hull, as shown in the last picture, appear shaky. It may have trouble twisting, but not due to the rigging, and certainly will have structural problems. Need more frames and some strong longitudinal member. But we must assume that it is not finished yet.
    This is what I mean by twisting the hull.
     

    Attached Files:

  12. gonzo
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    gonzo Senior Member

    Study basic boat structures and maybe you'll figure it out. Some people can't though.
     
  13. SukiSolo
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    SukiSolo Senior Member

    Preferably with a small return too. In sheet metal work it's known as 'Picture Framing' and it significantly stiffens a rectangular (or square) panel. Most dinghy gunwhale structures perform create a not insignificant stiff beam along the side which generally help take rigging loads and bodies hiking...;)
     
  14. rcnesneg
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    rcnesneg Senior Member

    This picture was before it was finished. Now, it has fiberglass inside and out, so it is very rigid, and thick gunwales running around the whole side of it. If I convert it to a sailboat it will also be getting full decking. The picture is just to show the current internal layout.
     

  15. TANSL
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    TANSL Senior Member

    Yes, that's what I thought. Anyway, I would have put a couple of extra frames. Could you show us a photo finished ?.
    The mast does not have to force you to put an entire deck. You do need to provide good support for the mast and rigging.
     
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