Monday, July 8, 2013

The Utility, part 6: Fixing the chines

I made a common mistake when I installed the chines. Sure, I'd read about the possibility of making this mistake beforehand. However, I obviously didn't "get" it. Happily, it's a common mistake with a fairly simple fix. I'm going to share all this with you in hopes that the new builder might avoid this pitfall.

The mistake is: not getting enough twist in the forward section of the chine log.

The resulting problem is: inadequate twist in the forward section of the chine leaves you with NO SURFACE AREA for the side planking to mate to.

Here's an image to help illustrate:

You see, after the chine and sheers are installed, both of these pieces are faired. The forward section of the chine is basically beveled along a line running down the middle of the wood from the stem to the forward frame. The upper (top-side) section of this bevel is where the lower edge of the side planking will attach. The top-side edge of the planking will attach to the sheer (shown as the dashed white line in the photo).

If you do not put an adequate twist in the forward section of the chine, then the resulting angle will not point outward adequately to the sheer line. This problem is illustrated by the dashed red line in the photo.

To avoid this problem, be sure to twist the chine adequately in the direction shown by the green arrows before you permanently attach the chine to the stem & frames. I did not twist mine adequately, because I thought the wood was going to break. So what. Soak it, steam it.... whatever you have to do to make it twist enough. Otherwise, you're going to have a problem to fix — just like I did.

The Fix:

The fix is: add a wedge-shaped strip along the top-side half of the forward chine, so that you'll have an adequate angle toward the sheer & enough surface area to attach the planking to after fairing.

The Utility's chines are 2 inches wide. The distance from the tip of the stem to the forward frame is 4 feet. So, I ripped two 1-inch by 4-foot sections of wood from the remnants of my first chine log (which broke because I didn't steam it).

I placed a straight edge from the chine to the sheer, and measured the angle. I then beveled my new "chine strips" so they would angle 20 degrees outward from the surface of the installed chine log. The resulting strips were fairly thin.

Cross-section of the "chine strip" after beveling it 20° on a planer / jointer.
I then epoxied these strips onto the top-side half of the forward chine. They were a little long, so I had to trim them. They bent easily since they were so thin. Now, I should have an adequate surface area for fairing & attaching the side planking.

Forward end of the attached chine strip, trimmed along bow line.

Aft end of the chine strip at the forward frame. This will have to be beveled down to make a fair curve along with the rest of the chine log.

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