A question about the Bolger Brick

Discussion in 'Boat Design' started by clmanges, Apr 4, 2021 at 6:28 PM.

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  1. clmanges
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    clmanges Senior Member

    When I saw the drawings for this boat I was surprised that the mast was located as far to the starboard side as possible. The reason given was to free up as much interior space as possible in the boat (the leeboard is on the outside of the hull for the same reason, I assume, and also on the starboard side).

    I just have to wonder if there's any other significant advantage or disadvantage to this arrangement. I've only been able to think of one advantage: that when running direct downwind, the boom can be swung off to the port side, and if everything was put together just so, the sail's center of effort could wind up pretty close to the boat's longitudinal centerline, giving a level ride, and, I assume, unbiased rudder.

    I think tacking and reaching might be weird, though; I'm guessing that the boat might heel more to one side than the other.

    What say ye?
     
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  2. bajansailor
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    bajansailor Marine Surveyor

    Some info about the Brick for reference -
    Brick https://www.duckworksmagazine.com/03/r/excerpts/bwaom/01/brick.htm

    Bolger Brick.jpg

    I was trying to find a photo of one sailing on starboard tack, as I was thinking that the sail would become more in the way of the crew then, but maybe not, especially with such a high boom (less chance of bashing your noggin).

    This photo illustrates nicely how the rig is offset -

    Bolger Brick sailing.jpg
     
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  3. cluttonfred
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    cluttonfred Junior Member

    Hehe, while the link goes to Duckworks, I recognize the blue-tinged drawings and photo as pics from my old site, still visible though incomplete here: brick - molepages. I am not much of a sailor, but my general recollection is that it made little difference what tack you were on in a boat so dominated by crew weight. On either tack, the leverage of the crew is enormous (you can see we're actually heeled the "wrong" way at the moment the photo was taken). I sold the boat when we went overseas and it soldiered on for quite a few years in the hands of Lincoln Ross, who sent me a pic of a bunch of little kids in it with him at one point. Here are a couple more pics:

    brick16_lightair.jpg brick18_boatbabe.jpg

    For getting a couple or young family out on the water at the local pond, lake, gentle river, or sheltered cove, I think it's a fantastic design and a great way to get your feet wet in boatbuilding. It's simple, cheap, fun, and easy to cartop (I transported mine on two cross bars clamped to the gutters of an old Peugeot 505 sedan). The exact same sail is used on several other Bolger/Payson designs (Cartopper, Elegant Punt, Gypsy, June Bug, Rubens Nymph, Surf, Sweet Pea, Teal, maybe more) so you could start with Brick and then build something a little more complex later on using the same rig.
     
    Last edited: Apr 5, 2021 at 9:14 PM
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  4. Will Gilmore
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    Will Gilmore Senior Member

    It's so basic, it's highly innovative. I love the idea of it.
     
  5. cluttonfred
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    cluttonfred Junior Member

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  6. sharpii2
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    sharpii2 Senior Member

    The disadvantages are:
    1.) The Center of Area (CA) of the sail rises as the boat heels on a starboard tack (it sinks on a port one). This is because the mast is stepped far from the boat's lateral center of gravity.
    2.) the boat may handle different on one tack than another. On the port tack, for instance, the boat may experience more weather helm than on the starboard one. This is because, on the port tack, the horizontal CA of the sail is far from the centerline of the boat, where, on a starboard tack it is much closer to it.

    This effect will be far less pronounced on a scow or a catamaran than it would be on a nonohul with a pointed bow. This is because, when a scow or catamaran heels, it's lateral center of drag moves to leeward much more than it does on a pointed bow boat. This is especially true if the scow uses Lee boards, and the catamoran has its keels or center boards mounted on its hulls.

    The designer has to be careful not to Lee helm on the starboard tack.
     
  7. Will Gilmore
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    Will Gilmore Senior Member

    Very nice and well reasoned explanation, sharpii2.

    Do you thing you could fix that with asymmetrical leeboards?
     
  8. cluttonfred
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    cluttonfred Junior Member

    There is nothing to fix, Brick serves its purpose just fine. You guys are trying to put spoilers and a whale tale on a golf cart. :-/
     
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  9. sharpii2
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    sharpii2 Senior Member

    Probably not.

    What would likely work better is having just one 'board, and having it on the starboard side.

    This is because the board produces most of the drag, while it is trying to create lift.

    The 10ft scow I'm building will have a single Lee board that gets shifted to the Lee side with every tack. It is set up so, that when the boat is on a starboard tack, it ends up further forward than when the boat is on a port tack.
     
  10. clmanges
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    clmanges Senior Member

    What's your reason for doing this? Is there some asymmetry elsewhere in the hull or rig?
     
  11. sharpii2
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    sharpii2 Senior Member

    Yep.

    Looks like I forgot to mention that my 10 ft scow will also have a offset mast. It will be stepped in the starboard side deck.

    I chose this arrangement, because my scow will have no fore deck, so I can step on board over the bow.

    I intend to use it as a fishing boat on small lakes.
     

  12. clmanges
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    clmanges Senior Member

    Regarding your asymmetrical placement of the leeboards, could you elaborate further? Some simple sketches would be nice, showing wind direction and reaction. Also, there's this solution (scroll down to "Paxton ..."):
    Types of Daggerboard leeboard centerboard etc https://pdracer.com/keel/

    I wonder if you aren't simplifying your design at the expense of extra operating labor by having only one leeboard and switching it from side to side. I like being lazy--and being able to react quickly--so I'd favor one on each side, independently controllable. Having only one also seems to work satisfactorily, as witness the Brick itself, and a lot of PDR builds.

    Finally, I wonder how much you'd even notice the effect, as cluttonfred commented about crew weight in post #3. I suppose that might be mostly a function of your hull shape.

    I'm just guessing and trying to learn here; I have no sailing experience at all; I just paddle.
     
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