Saturday, July 27, 2013

Working on the Zip

This blog started off with a reference to the Zip plans I had just ordered back in April. The plans arrived a week after I made that first post, and I got started on the stem that very weekend.

During breaks while working on the Utility, I have slowly & purposefully been working on parts for the Zip. I have been taking my time, carefully shaping the parts. I'm in no rush at this point, since after all I still have the first boat to finish.

I've made it a point to cut just outside the lines on the parts so far, then sand them down to the line. So far I've got the stem shaped, as well as the lower piece of the breasthook. I cut the top piece of the breasthook earlier today. Not much to show so far, but here are some photos.

Tracing the stem onto 3/4" Douglas Fir marine plywood.

First stem piece cut. Using it as a template to trace out the second piece.

Carefully filing out the notch in the lower breasthook piece.

The shaped Zip stem needs to be epoxied. Construction on the Utility is underway in the background.

Fairing the Utility

I have been slowly and cautiously fairing the Utility. I still have a long way to go, but I am making progress.

"Fairing," in case you didn't already know, is the process of beveling all of the parts of the sub-structure of the hull (frames, stem, chines, breasthook, transom, etc...), so that the plywood planking, when added, will have properly-angled surfaces to mate to.

For the newbie amateur builder (ie: Me), it's probably the most daunting and intimidating step of building a boat. However, it's a necessary and extremely important step.

I started by fairing the aft bottom section of the boat. Testing with a couple of plywood pieces shows that I've got some slight gaps between the outer floor battens and the inner surface of the bottom planking. I'm planning to fill these gaps with thickened epoxy when I attach the planking.

I've done preliminary fairing on the bottom of the chines up to the forward frame.

Over the last several weeks, (since adding the chine strips described in my last post), I have been fairing the forward bottom section. Most of this work has been on the starboard side. I've been using the Rabl method for fairing this area. The Rabl method was developed by Sam Rabl, and is described in detail on the Glen-L website here:

For me it is slow work. I've been using a couple of sizes of hand planes and a belt sander, and checking progress frequently with straight edges and my plywood test pieces. My recommendation to the new builder beginning the fairing process would be to simply take your time. Proceed slowly, check your work frequently, and expect this stage to take a long time. It's easy to try to hurry the work along, then inadvertently create gaps or gouges that you'll have to fix. (Trust me.)

I've still got a long way to go, but I will share some photos of the progress so far.

Fairing the stem

Fairing work in progress at the stem, chines and forward sheer.

Slowly bringing everything together to a point at the bow.

More fairing work has been done on the starboard sheer than on the port side so far.

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.