My Backyard Boats:

Moby Dink -- Skeg

 

    28 September 02: Making a skeg is an exercise in scribing a board to fit the curve of the hull. If you don't feel like wasting Select grade wood, make a template first. I did. Making a skeg requires a lot of little skills and shop tricks, so it's a good photo op. I took a bunch. The skeg came out fine.


Step One: Take a scrap of plywood -- any scrap at least 24 inches long and 12 inches high, say, to use in making a template of the skeg. This will save on wood-eating mistakes. Scribe a line with a pencil on the plywood by putting the pencil down on the hull and pulling it toward you. If the curve of the hull is too severe, use a block to hold the pencil up some, then scribe the line.
Step Two: Using clamps, secure a straight-edge, such as the rafter square that I used, on the centerline of the stern. Scribe a line on the plywood to set the back angle of the skeg to make one angle with the stern.
Step Three: Measure up four inches (in this case) at the stern end of the plywood and mark. Run a batten from the forward edge of the plywood to the stern edge and scribe with pencil. This is the top of the skeg. The top of the skeg generally is level with the deepest point on the hull. BTW: The skeg helps the boat track straight when rowed.
Step Four: Cut out the plywood on the line that matches the curve of the hull. Check for fit. Sand or plane, with block plane, to make it fit reasonably well. Since we're using epoxy, the fit can have gaps, because epoxy bridges gaps and is actually stronger because there is more epoxy. I shoot for the best fit I can get, or gaps no more than 1/32, whichever comes first. I need the practice.
Step Five: I used a 1x10 board of poplar that I had lying around. The finished plywood template is shown on top of the poplar board.
Step Six: The skeg has gaps that exceed my tolerances, so I grind some and plane some to make it fit. Photo shows initial fit.
Step Seven: After planing and grinding to make the skeg fit the curve of the hull, I check to ensure that the skeg is perpendicular to the hull. This being a flat-bottomed boat, this is easy to check.
Step Eight: Since the hull needed to be faired after the previous day's application of epoxy, I went ahead and faired, since the skeg would making fairing harder if it were installed before fairing. The hull went from beautiful and shiny to faired and dull, which is what you shoot for. Shiny areas are usually low. I like to use a random-orbit sander for fairing. When I need a more aggressive cut, I angle the sander some until the area in question becomes dull and fair. The fiberglass tape that I re-applied was acceptable. Just needed another coating of epoxy after some aggressive sanding with a small belt sander.
Step Nine: After the fairing is finished, I run a chalk line from stern to bow. This is when one is glad if there is a dark pencil line or two to show the centerline.
Step Ten: One view of the installed skeg. I didn't used any screws through the hull, just epoxy thickened with wood flour to bed the skeg and to make a bead on each side. (I refuse to refer to such a bead as a fillet, because I have no idea why  a word that describes a cut of meat would be used to describe a line of glue ... . While I'm at it, I cringe when folks talk about buttering a joint with glue; sounds kinky to me, I guess.)
Step Eleven: Eyeball the alignment of the skeg fore and aft to make sure that it's on the centerline. It's a good idea to check that the skeg is still perpendicular to the hull. Thickened epoxy sits at least 1/32 deep and can throw you off by that amount or more. I don't used screws here because the epoxy is so strong. I have bedding compound but use epoxy almost always instead.
Step Twelve: Throw away all the epoxy that thickened too quickly. Just shake it off. Stuff happens. You done good today. Claim it.

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