Fiberglass Rudder Shoe

Discussion in 'Boat Design' started by CharlieDanger99, Aug 4, 2022.

  1. CharlieDanger99
    Joined: Jun 2021
    Posts: 22
    Likes: 3, Points: 13
    Location: Tampa Bay

    CharlieDanger99 Junior Member

    Admittedly I know next to nothing about carbon aside from carbon = stronger, but it sounds like I may want to just rule that out for now. I supplied some sketches above for reference. The reason I would want to laminate in a female mold is as you described the issue of the protrusion to accept the rudder stock. If you imagine a cross section, the shoe is essentially a series of U shapes of progressively shorter height. I would need to make a template for cutting the glass by wrapping paper/cloth around the original shoe and I've had little issue coaxing glass into tighter radii than the edges of this U shape. This would ensure each fiber spans the whole length of the part, and with some relief cutting I should be able to get each layer to double over in the aft protrusion to fill in that section, followed by more small layers to bring the solid potion up to the slot for the keel. A small rotary tool and some thickened resin would work to get a snug fit in the slot, and once it fits well over the keel I can pull it off and use a pattern from the original to mark the location for drilling out the bore. The weakest portion of the shoe would be the protruded section where it meets the keel, and I can easily build up the thickness here over the original profile to increase resistance to lateral loading.

  2. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    The constraint is going to be stiffness and not strength. With less stiffness, the gudgeon (not a shoe, that is something different) will deform and the bushing will get out of alignment. That will create more wear, bind the rudder, or both. You need to design it to be as stiff as the original bronze part.
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