Leeboard on small skiff

Discussion in 'Sailboats' started by hospadar, Jul 20, 2011.

  1. hospadar
    Joined: Apr 2011
    Posts: 63
    Likes: 3, Points: 8, Legacy Rep: 30
    Location: Michigan

    hospadar Junior Member

    I'm going to be installing a leeboard on a small skiff. The sides of the skiff are raked out (at about a 105 deg. angle), so if I bolt the leeboard flat to the side it won't be perpendicular to the water.

    I'm wondering if it's worth it to put spacers on the hull (down by the waterline probably, I'm imagining a ripped-down strip of 2x4) to get the leeboard to be more perpendicular to the water.

    It's just a little 12' fun boat It's my first build so simplicity is more important than maximum speed, but if the rake in the leeboard is really going to hurt my ability to sail, then I'd like to get that straightened out.

    Another question I have is about positioning the center of effort of the sails with relation to the leeboard.

    I've read that the CE should be forward of the centerboard, but I've also heard that with leeboards, the CE should be right on top of the leeboard. Again, this isn't that important, I don't care if I have a little weather helm or imperfect performance, I'm just wondering how much it matters.


    Thanks again - I can't wait to sail this puppy!
     
  2. CutOnce

    CutOnce Previous Member

    I'd just clamp it on and try it on a light day. That way you could move it around till it felt right. Once you determine empirically where it belongs, you could then get fancier with the hull standoff etc.

    It's small enough that you can experiment.

    --
    CutOnce
     
  3. BATAAN
    Joined: Apr 2010
    Posts: 1,614
    Likes: 99, Points: 0, Legacy Rep: 1151
    Location: USA

    BATAAN Senior Member

    In Peru they take a piece of 1 X 10 maybe 5 or 6 feet long, nail a crosswise 24" 2 X 2 to one side about 12"-18" down from the top, and nail on a piece of lead sheet to the other end to weight it so it does not float. This stuff is often scavenged from pallets or old buildings.
    A hole is drilled in the top of the 1X10 and another in the middle of the appropriate thwart. A piece of 3/8" rope with stopper knots connects the two holes.
    To use you throw it over the lee side and the 2X2 rests on the gunnel, the leeway pushes the 1X10 vertical until the rope comes tight and also holds it in place.
    To adjust for neutral helm you slide it fore and aft, adjusting the rope a little if necessary.
    To tack, throw it over the other side.
    No bolts or hardware, infinitely adjustable, costs almost nothing, etc.
    I sometimes wonder why things get so complex.
     
  4. Plodunkgeo

    Plodunkgeo Previous Member

    Maybe because the very act of having a significant element of the sailing experience unattached, highly moveable and vulnerable to not being able to work, or worse, being lost overboard, makes for a really problematic scenario?

    Ever lost an important tool over the side? Why?
     
  5. Doug Lord
    Joined: May 2009
    Posts: 16,679
    Likes: 342, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    =============
    Some designs that use leeboards use two with only the lee board in use at any one time. That can have some advantages including making the angle of the board virtually irrelevant. If you use just one board, the angle due to the sides may have a small negative effect when it is to windward.
     
  6. GTO
    Joined: Jul 2007
    Posts: 143
    Likes: 9, Points: 18, Legacy Rep: 101
    Location: Alabama

    GTO Senior Member

    Depending on the amount of flare at the placement point, it will be noticeable on the "bad" tack but probably not terrible.

    A bigger concern will be getting the board parallel to the skiff's center line.
    My board is a bit off and on the "good" tack the boat climbs to windward.

    To get the angle for the board, I built the following rig:

    I took a small block of 2"x4", attached a piece of AL angle to the edge leaving a 1/2" gap and ran a bolt thru the block. This I dropped into the oarlock socket.

    Clamped a 2"x2" to a thwart (hanging over the gunwales) and placed eyebolts in both ends.

    After U-bolting a 1/2" round tube to a piece of ply acting as the leeboard, I slipped one end of the tube into the eyebolt and the other into the oarlock "clamp".

    By screwing the eyebolt in or out of the 2x2 I was able to get an angle and sliding the board fore and aft yielded a decent location.

    I actually sailed with this rig for awhile, but flipping the board side to side was a hassle and I had to stop after a tack to do it.

    I hope that gives you some ideas to try.
     
  7. BATAAN
    Joined: Apr 2010
    Posts: 1,614
    Likes: 99, Points: 0, Legacy Rep: 1151
    Location: USA

    BATAAN Senior Member

    Maybe the post was not clear. A rope fastens the leeboard to the boat at all times. This is a little too simple for some. And it always works.
     
  8. troy2000
    Joined: Nov 2009
    Posts: 1,743
    Likes: 170, Points: 63, Legacy Rep: 2078
    Location: California

    troy2000 Senior Member

    Having one leeboard on a line that you can flip from one side of the boat to the other as you come about isn't exactly unheard of, especially on very small craft. I'm not sure why you're reacting so negatively to the notion.

    And personally, I've never lost a tool over the side, as long as it had a line attached....:)
     
  9. troy2000
    Joined: Nov 2009
    Posts: 1,743
    Likes: 170, Points: 63, Legacy Rep: 2078
    Location: California

    troy2000 Senior Member

    From EF Knight:
    add: If I remember right, Ian Oughtred's Wee Rob has the same sort of setup when it's rigged for sailing. And here's a thread that also discusses the single-board-on-a-rope method: http://www.boatdesign.net/forums/boat-design/designing-weak-failure-point-leeboard-19791.html

    The thumbnail is below is from Knight, not Oughtred:
     

    Attached Files:

  10. hospadar
    Joined: Apr 2011
    Posts: 63
    Likes: 3, Points: 8, Legacy Rep: 30
    Location: Michigan

    hospadar Junior Member

    I think I'm going to try the roped leeboard first, it'll give me good opportunity to experiment with position/size/rake angle, since it should be easy to juggle around and change boards. If I determine it's too much of a hassle, or fails in choppy water (the great lakes) or unpredictable winds, I may change it out. I imagine in general though, if there isn't enough leeway to hold the board to the boat, that the board isn't that crucial at that moment anyways (i.e. running).

    Instead of a flat board I'll probably make a symmetrical foil (since the leading edge will flip-flop when tacking), and (just because I've always wanted to do it) I think I'll pour a lead weight into the bottom.

    I'll report my findings when I give it a go.
     
    1 person likes this.
  11. troy2000
    Joined: Nov 2009
    Posts: 1,743
    Likes: 170, Points: 63, Legacy Rep: 2078
    Location: California

    troy2000 Senior Member

    Keep us posted on your progress; you can have a whole lot of fun with a boat that size.
     

  12. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 484, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    You've got a simple boat, why not use a simple attachment. The board doesn't need to pivot up and down, it's either deployed or it's being moved or stowed. A simple "U" shaped plywood and 1x2 bracket that permits it to drop down over the rail, is all you need. This can be slid fore and aft to find the sweet spot, which will likely be with the CE directly over the leading edge of the board. The bracket can provide for a perpendicular orientation to the water as well. A sung fit will insure it stays put, but a whack with the heel of your hand can convince it to come off, when you want to switch sides or stow it. This arrangement has no moving parts to break or get lost and is the most common method for this type of appendage on small craft. Bolger loved this setup too.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.