JoeBoat Alana

Discussion in 'Sailboats' started by sharpii2, Nov 1, 2020.

  1. sharpii2
    Joined: May 2004
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    Location: Michigan, USA

    sharpii2 Senior Member

    After many years of playing with boat design, I have decided to finally take the plunge into the designer/builder realm.

    I have decided to build a boat of my own design.

    If this boat proves itself, I'm seriously considering creating a class based on its design.

    The design is what I call a "JoeBoat" (named after my long deceased brother). It is a concept I have long ago wanted to try. It is a straight-sided scow with a 3.0 ft Beam and a deep-rocker bottom.

    I have drawn four versions of this concept, complete with full parts drawings.

    It started out as a 2.5 ft x 10 ft boat, then morphed to two 3.0 ft x 12 ft versions, then finally became a 3.0 ft x 10 ft boat, the one I decided to build.

    Not content to build just a hull and put a conventional rig on it, I decided to also try a sail concept I have been kicking around for many years, too.

    I have been wanting to try a split-lug for as long as I can remember.

    A split-lug is a lug sail that is split into two smaller sails which share a boom and a yard. The aft portion is laced to the mast. The forward portion is free standing in that it only attaches to the boom and the yard.

    There are two supposed advantages to this arrangement:

    1.) there is no chafing against the mast on the "bad tack", as there is far less of one. The boom and the yard are still on one side of the mast, so there is a difference in tacks, but the sail cloth does not have to bend around the mast.

    2.) A larger portion of the sail area can be in front of the mast. This will be useful for better down wind manners and less violent jibes. It also will allow the mast to be stepped further aft, which will be quite useful on a tiny boat.

    A big disadvantage, however, is reefing.

    If the sail is to operate properly, the luff of the forward part must align properly with the leech. And the leech must align properly with the luff of the aft portion. Once a reef is tied in, this alignment can go to Hell.

    As a solution to this problem, I added a second boom to define the upper portion of the reef slab.

    This effectively creates another pair of sails, a lower forward portion and a lower aft one. By lowering the top boom onto the lower one, the sail is quickly reefed--providing lazy jacks are used.

    It will share this characteristic with a Chinese lug .

    As for the hull.

    The idea is to have a shorter WL when the boat is dead upright and a longer one when it is heeled.
    Also, the boat can heel quite a bit before the bow transom corner digs in.

    A further advantage is that it can be ran up to a bank and be more easily be pulled up it.

    For deck layout, I decided to board over the bow, so the side-decks run straight up to the bow transom, and there is no fore-deck. This way, I don't have to climb over the rudder, or unship it, every time I board.

    The mast is stepped through the starboard side deck, so it becomes a handy hand grab instead of an obstacle.

    So far, I have built the rig (which I hope to show below), and I have fully lofted the hull.

    This will be the first boat I have built in over 40 years.


    FinishedRig.jpg Alanna3.png Alanna2.png
     
  2. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    Some thoughts :
    Your beam is only 3' - methinks she might be a tad tippy?
    Your rig looks rather complicated - you effectively have to make 4 sails (although the two forward ones are just glorified pocket handkerchiefs).
    With the mast stepped through the starboard side deck, this would work very well for sailing on port tack - but you won't be able to 'sheet in' very much on starboard tack without the boom bashing you.

    Re creating a class, I admire your optimism - but I think I would prefer something like a Minifish any day - this is essentially a smaller version of the Sunfish.
    https://sailboatdata.com/sailboat/minifish
    11'9" long, and 3'10" wide - that extra 10" will have a huge effect on the stability, never mind that she has a pointy bow.
    Oh, and they apparently built 14,000......

    In the 70's we had a popular home grown class called a Kingfish here in Barbados - it was very similar to the Sunfish (it used the same rig), but built of wood with a bluff square bow, and with no cockpit at all - you sat on it, rather than with your feet in a well. And it was a very popular and competitive class here, but I cannot find any mention of it online.
     
    Last edited: Nov 1, 2020
  3. messabout
    Joined: Jan 2006
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    Location: Lakeland Fl USA

    messabout Senior Member

    Looks like a PDR that has gone to school. A Narrower, longer, more symmetrical rocker. The sail................? a PITA on first impression. Until you persuade me, I am wondering why I need to mess with additional control lines for so tiny a boat. At 36 inch beam it will be nervously tender unless the sail is kept too small for meaningful drive. . Increase the beam to 40 inches and gain a lot of stability both initial and heeled. This kind of boat will have some exaggerated section centroid alignment problems when heeled at moderate degrees.. 5 8, 10 degrees.

    Aside from all that criticism, I like the boat but not the sail. The sail is inventive so I defer to your judgement. Carry on, this is interesting.
     
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  4. sharpii2
    Joined: May 2004
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    Location: Michigan, USA

    sharpii2 Senior Member

    Thank you bajansailor for commenting on my design.

    The narrow beam is somewhat deceptive. This is because stability comes from average beam, not maximum beam.

    Stability also comes from Vertical Center of Gravity (VCG) placement. The seat in this boat is just 6.0 inches above the bilge. If it were higher, the boat would indeed be tiddly.

    The sail plan is also modest, even considering the narrow beam.

    The sail, indeed, is a concoction. It is based in principle on a sail I made over forty years ago. It was to power a four-man raft I had turned into a sailboat.

    The sail proved to be surprisingly effective, especially to windward. It was made of plastic and duck tape, but out sailed a grp dinghy, of similar size and weight, to windward.

    I was quite surprised. The race was suppose to be a a joke. This other boat had a dacron sail and a proper dagger board.

    Mine had home made sails and twin boards whose blades were longer than they were deep.

    The theory is that the "handkerchiefs", in front of the mast, will direct air flow around it, so there is less turbulent flow.

    I do have an exit strategy should this not work out.

    I have already designed a more conventional balanced lug, which will have similar area, and use three of the four spars.

    I do remember a plywood board-boat which used the sunfish(r) rig. And it didn't have a foot-well, and it had a square bow.

    Sunfish(r) were a bit pricey back then, and I suppose this plywood boat was a build-it-yourself alternative. I remember seeing a lot of them around.
     
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  5. sharpii2
    Joined: May 2004
    Posts: 1,955
    Likes: 137, Points: 63, Legacy Rep: 611
    Location: Michigan, USA

    sharpii2 Senior Member

    Thanks, messabout. I do remember the PDR days. I used to hang out there a lot. I even designed two PDRs myself.

    Only 4.0 additional inches of beam will improve the stability more than one would think.

    But if the boat already has sufficient stability, why add more?

    Granted, the sail drawn has relatively modest area for a dinghy, and greater beam and a greater sail area would certainly improve the performance over a greater range of conditions.

    But I do belive both are sufficient for my purposes.

    This is not intended to be a pure sailboat. There are plenty of them around (and probably designed by better designers than myself).

    Much of the time, this boat will be propelled by muscle power.

    If there's not enough wind for proper sailing, I want to go boating, damn it.

    Maybe I can drown a few worms then and bring back my supper.

    I don't see a problem with the centroid issue (of course I can be wrong). What I may end up with, when the boat heels, is an asymmetrical catamaran hull, with rhe flat side of the "V" bottom to leeward, where the drive of the sail will be (at least on the port tack). The flat side may also provide enough effective lateral area to allow forgoing the 'board. But the rig may be too far forward for this.
    But I will try this when I do sea trials.

    Yeah, the rig may be a bit much for a tiny boat. It does seem to be damnedly complex. I sure felt this when making the extra spar, the four separate panels, and the lazy jacks.

    But only one extra step is added for set up time, and once the various leeches and luffs are aligned (which will probably have to be done only once when the sail is first used), the sail may prove easier to use.

    Reefing will be possible while still out on the water, and maybe even while under way.

    With a more conventional rig, the boat would probably have to be beached first.

    Besides, this can be seen as scaled down test of concept for a larger sail in the future.

    Even at its present size, I can imagine two of these on Sven's ExLex, instead of the two rectangular balanced-lugs he has now. These would almost double his sail area while making reefing a whole lot quicker and easier.
     
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