retractable centerboard

Discussion in 'Sailboats' started by billdog, Aug 29, 2009.

  1. billdog
    Joined: Aug 2009
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    billdog New Member

    I have a 1986 Seidelmann Sailboat Model S295. It is a 30 footer with a 3' 6" shoal keel.
    The keel is retractable into an encasement. The keel has fallen off and been lost at sea.
    Seidelmann went out of business in 1986 and was not bought by anyone.
    Does anyone know or know where I could find the specs to this centerbord.
    Are they similar between boat manufaturers.
    Or does anyone have a any ideas

    Thanks
     
  2. alan white
    Joined: Mar 2007
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    alan white Senior Member

    They are not the same between manufacturers. My suggestion is you find a sister ship and first ask what material the board is made from.
    Then you need to create a pattern from perhaps foam insulation board or thin plywood . This may involve a Travellift to get the boat up in slings for a while. Thickness is critical, with sufficient clearances. It's easy to subtract a half inch from the leading edge, trailing edge, and top, but the side to side clearance should be sloppy enough to allow for various kinds of scum and marine growth which often happens when the trunk can't easily be anti-fouled.
    I think I'd want a total of at least 3/8" but others may have their own ideas on that clearance.
    The axle or pivot bolt should align your drill to locate that hole, and lastly the cable eye for raising is x number of inches aft of the pivot, and that's where the attachment is made, by one of several methods depending on material.
    If steel (maybe the original was iron or steel), it's quite easy to make a new one with a cutting torch, a grinder, and a drill press.
     
  3. billdog
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    billdog New Member

    thanks for the reply
    I do have some information about the location of some sister boats
    I do remember that the old centerboard was fiberglass and had a shape to it
    I think the shape was thinner on on the leading edge and the trailing edge .
    I am not sure what the core was. I guess it does not matter. I could use what ever would be the best material for the core at his point. I can get a
    pretty good idea of the old overall dimensions because I remember how the old board sat in the cavity. I guess I am most concerned with shape and weight of the old centerboard. I would imagine that the board was
    weighted more at the bottom edge to make it drop down.
    Do you know of a designer or website that could figure the best design for the board. I do have the overall ballast and diplacement specs of the hull
    but do not know the split between the centerboard and the stub. Is there a basic formula for ballast split between the stub and ceterboard. My boat was built for speed and is not a blue water cruiser so I would imagine that everything was built as light as possible.
    I am sure with some guidance I could make and install a new centerboard.
    Thanks
     
  4. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Unfortunately, though there are formulas and other "tools", each design is application specific in regard to board shapes, weights, location plan form, etc. In fact ever aspect of the design will be like this.

    It's very likely your board was ballasted, not just weighted and that shapes were well defined. Where are you located?
     
  5. alan white
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    alan white Senior Member

    A lot of times I've had to design parts for which no drawings were available, and nothing to copy. Rudders especially on small boats (the sea floor must be littered with them).
    I don't like centerboards on larger boats. They are a pain to access for any maintainance (time consuming and expensive), and so a lot of otherwise well-maintained boats have problems creeping up that aren't being monitored.
    The best setups I've seen have a top cover for the case. It's possible to get the board out from above. Controversy sloops had them, and actually, a lot of wood boats with slotted ballast keels did, but few fiberglass boats.
    I have replaced cables before and painted the board and case but I had to pay for the slings to be tied up for the required time.
    The only sensible answer is a cradle tall enough to allow maintainance, with support fore and aft of the slot.
    The height of the board when horizontal shouldn't exceed 18" or so on your boat, and likely less, so I'd recommend you alter your cradle if you use one and allow for getting in there to work, and to regularly maintain the board in the future. A trailer is problematic owing to axles and the roller track in the center, and slings just cost too much unless the boat yard owner is your brother in law.
    Frankly, the exact sectional shape of the board is not going to require knowing what that particular boat had, just a shape copied from any good sailing boat's board. Most important is that the angle of the board is correct when down all the way. That is going to be harder to accomplish. You may have to use slings for that and glass in blocking or whatever works, knowing beforehand what the angle is supposed to be based on a drawing from the original design.
     
  6. PAR
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    PAR Yacht Designer/Builder

    It depends on what type of board is employed (slice of pie, high aspect, etc.) as to the plan form, which is often affected by the hoisting arrangements as well.

    All my board designs have a removable case top, but it's an over looked item as Alan mentioned.

    At the very least, a reasonably accurate sail plan and yacht spec's will be necessary to pen up a new board. Having accurate weights would be very helpful.
     
  7. ancient kayaker
    Joined: Aug 2006
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    ancient kayaker aka Terry Haines

    A Google search for "Seidelmann Sailboat Model S295" turned up several sites including this one http://seidelmann-owners.com/S295_ALL/index.html
    which will at least give you the basic dimensions and weight from which you should be able to design something suitable to fit your boat. Good luck!
     
  8. billdog
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    billdog New Member

    I know about the website. My boat is listed on there. The name is the Virgil.
    The website does list the general specs from the original sales brochure.
    It does not have specs for the S295model centerboard. I have found out that the centerboard was made of fiberglass and did not have ballast except maybe some and the stern end to drop down. I have had the board down on the lift in the yard to try and inspect it to best of my knowledge the board would drop straight down and was not on an angle. The pin and lift mechanism are all inside
    the cavity and not accessable from inside the boat. The local guy who does work on my boat has a theroy that the pin was eaten away by electrolisis?
    I was think about just filling the cavity with about 600lbs of ballast weight and leaving it at that?
    What do you think?
     
  9. alan white
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    alan white Senior Member

    You know how she sails without the board. But unless the boat was improperly designed, I wouldn't add ballast as you'd lose good cruising capacity and speed too.
    I don't know how easy that would be either, probably a lot more work than building a new board.
     
  10. billdog
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    billdog New Member

    tartan 27 centerboard

    I have found out that Tartan27 B Centerboard was very similar to the centerboard on a Seidelmann 295CB. Does anyone know where I can get the
    specs on a Tartan 27 centerboard?
     
  11. Zoomtoob
    Joined: Aug 2015
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    Zoomtoob New Member

    seidelmann s295 - NO CENTERBOARD!

    I cannot find a flippin centerboard on my boat - anywhere!!! is it supposed to be there? I was told 84s and 86s have it but nothing there on my 85...

    help...
     
  12. PAR
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    PAR Yacht Designer/Builder

    Welcome to the forum.

    Is your boat out of the water? Have you looked for a centerboard slot, winch, hoist tackle, etc.? Are you the fellow from Somerspoint that had his centerboard drop off and needs a new one?

    I don't have a lot of information about this NJ built boat, but they did come with various trim issues, depending on how there where equipped. Many needed a modest amount of ballasting to get them to trim properly. My data base shows them as fairly well built and a hole in the aft face of the bridge deck, for the centerboard winch handle should be visible.

    I do know of at least one where the board was removed and an 18", 200 pound casting placed on the fin. Considering the compromised shape of this era yacht, not a bad idea for sailing performance.
     
  13. Zoomtoob
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    Zoomtoob New Member

    Hey PAR. Boat is out of water and there is just no centerboard. No slot, winch, line, pendant, cable pulley or anything. Definitely an 85. Just wanted to know if anyone else was out there regarding the S295. I did find a few hundred pounds of lead in the Stern bilge. Needs a lot of work. Fun project boat, now on the side of the house here in Marlton NJ.
     
  14. Apollo
    Joined: Jul 2016
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    Apollo Junior Member

    Same same

    I have a Seidelmann S295 without the retractable centerboard and would also appreciate a solution. I am in Washington DC
     

  15. PAR
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    PAR Yacht Designer/Builder

    Given the era, you'll be best advised just to make your own board, case and tackle arrangement. It's not especially difficult, though the engineering needs to be sound if you don't want it to leak and of course its appropriate placement for balance. The S245 used a stub keel and a similar arrangement to the one I usually employ, which keeps the case and tackle below the cabin sole. Of course, this increases minimum draft a bit (the S245 is about 23" board up), but an unobstructed cabin sole is nice. If you could live with a low case in the cabin (put a table over it), the draft can decrease to about a foot.
     
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