Cutting notches for the floor battens

As you may have noticed from the photos up to this point, I did not pre-cut notches for the floor battens into the frames. That's because I planned to use the optional arrangement of 3 battens per side, rather than the standard 2 battens as drawn on the plans.

I wanted to wait until I could actually lay the battens on the frames, and place them as I wanted. What I've decided to do is to use 2-1/8" battens spaced 7 inches centerline-to-centerline from the keel, then 6 inches centerline-to-centerline from one another.

Here's how I went about cutting the notches for the floor battens:

The inner battens are on 7" centers from the keel.

The floor battens are on 6-inch centers from one another.

The battens, (or at least the two I have at the moment), are about the same thickness as my ruler. So, I will use the ruler as a guide to mark some reference lines.

At the aft end, I make sure to hold the ruler even with the underside of the batten, not flush against the 12° rake of the transom.

Using the underside of the ruler as a guide, I draw a line with a pencil to show how deeply to cut the notch. 

Then, I clamped the batten into place and made some initial cuts, using the sides of the batten as a guide.

I used a block of wood with a 12° rake as a guide, so that the horizontal cut would be level, not angled like the transom. This block of wood is actually the former tail-end of the keel.

Here, you can see that I goofed one of the vertical cuts. Fortunately, it didn't get very deep before I noticed my mistake. I'll fill this in later, but hopefully most of it will get faired away when I get to that phase.

Using this block as a guide, I held the multi-tool blade against it as I made the horizontal cut.

Here's the cut through the transom.

And the fitting of the batten into the notch. Not bad.

That completes the notch cut into the transom. Now let's move forward to Frame #2.

As before, I used my ruler as a guide to mark the depth of the cut, since it's about the same thickness as the batten. The ruler is aligned with the edge of the frame, so that the mark for the cut will be at the same angle. (Remember that the boat is upside-down on the form, so what's showing is actually the bottom edge of the frame.)

Ruler aligned with the bottom edge of Frame #2.

I'll mark the line with the scribe that is built-in to my sliding square.

Line marked for the horizontal cut.

Cutting guide and batten clamped into position.

The vertical cuts were made by aligning the side of the multi tool's cutting blade with the side of the batten.

The horizontal cut was made by aligning the bottom of the multi tool's cutting blade with the top of the cutting guide. I made minuscule finishing cuts with a coping saw.

The batten drops right into place.

Now, to repeat for Frame #4.

Cutting guides clamped into position.

Notch is cut.

That line next to the notch isn't a cut. It's the end of a shim I laminated onto the frame earlier.

Batten drops right in.

Now, for the Limbers. These are openings in the frame, alongside the floor battens, to allow any water in the bilge to flow to the back of the boat for removal.

I used this roll of Duck Tape as a guide to scribe the curved line. Seriously... it's called "Duck Tape."

Curved line scribed onto the frame.

Making the rough cut with a coping saw.

The rough cut is easily finished out with a Dremel tool fitted with a sanding drum.

et Voilà

Working backward, repeat for Frame #2.

So there you have it. That's the procedure, or at least my version of it. Four more floor battens to go... but for the moment, I'm out of mahogany.

Keel, End-to-End

There are two main reasons why I chose to build a laminated keel.

The primary reason has to do with the upward bend that the keel makes at the forward end. A 1-inch thick mahogany board does not bend as easily as a board half that thickness. Not only that, but only the front part of the keel must bend... the rest of it has to remain perfectly flat.

Several Glen L. Witt designs use this technique. A common problem encountered by builders of Glen-L boats such as the Squirt and the Zip is that bending the forward end of the keel produces a bow in the aft section, where it is supposed to be flat.

My thinking was that, by having the aft section laminated to its full thickness of 1 inch, and leaving the forward section un-laminated at 5/8", the forward end would bend easily without disrupting the flatness of the aft end.

Simply put, it worked, and I'm glad I did it this way.

The other reason is that, by laminating, I could make a 14-foot keel out of shorter boards. While my execution of all this wasn't perfect, it does work.

So, on to the photos:

3-1/2" carriage bolts through 5/8" section of keel and the stem.

Holes drilled, test-fitting the transom knee.

I drilled the holes through the keel and transom by first clamping the transom knee into position firmly, then using the pre-drilled holes in the knee to drill from the inside of the knee outward. To do this, I used a 12" long, 1/4" diameter drill bit.

Transom knee temporarily bolted into position with 5" bronze carriage bolts.

Adding the final lamination to the keel. Note the forward holes to accommodate the carriage bolt heads that were already in place. The lamination was done with thickened epoxy and clamps only. No screws.

Transom knee epoxied and bolted into position.

Countersunk bolt holes, filled in with thickened epoxy.

Overhanging end of the keel cut off.

Epoxy fill sanded flush at the aft end.

Epoxy fill sanded flush, and a little pre-fairing at the aft end of the keel.

Epoxy fill sanded flush at the forward end.

Epoxy fill sanded flush at the forward end. 

The now fully-laminated keel. Note that I've started cutting notches for the floor battens.

Cutting limbers for the floor battens. More on that later.

So, the keel is on, and it's there to stay. Time to move on to the next step.

Installing the keel

Finally, I've reached the point of installing the keel on my Glen-L Zip.

Let's pick up where we left off: the transom knee needed a 7-7/8" tapered shim.

I made the shim, trimmed it to length, and epoxied it to the transom knee. After I sanded away the epoxy mess, it looked like this...

Trimmed & drilled

A little more primer...

Countersink the holes for the carriage bolts, so that the washers can land on a flat surface...

So, when I trimmed the shim, that obviously left a bit of a leftover piece. Keep that in mind. It comes into play later.

Now let's get to the keel installation. First, the prep work:

I'm embarrassed to admit that I had to Google how to properly install a carriage bolt in wood. But, one of the tenets of this blog is that I will openly share both my mistakes, and what I've learned, in an effort to help others. Surely I'm not the only person in the world who didn't know how to use a carriage bolt!

For those who don't know... the whole point of a carriage bolt is that you don't have to hold it with a wrench at one side while you tighten the nut at the other side. That's what the square part at the top is for. Drill a hole the same diameter as the bolt. Then, countersink the hole with a drill bit that is the same diameter as the width of the square part. Make sure you don't oversize this countersunk part. The square will drop right in, and grab hold when you tighten the nut. Pure genius.

Carriage bolt & countersunk hole at the keel-to-stem joint.

Marks on the keel, showing where to put the epoxy. This is the keel-to-transom joint.

Marks on the keel, showing where to put the epoxy. This is the keel-to-Frame #4 joint.

Marks on the keel, showing where to put the epoxy. This is the keel-to-stem joint.

I took someone's wise advise to cover all that finishing work I've done on the dash so far.

Safeguarding against gluing the frame to the construction form. Trust me... I learned from the Utility that it doesn't take much epoxy to cause you a real problem. If you use blue tape like this, be sure to remove it before the epoxy cures. Otherwise, it'll leave you one unholy mess to clean up.

Making sure Frame #2 is vertically level.

Okay. Remember the leftover piece from the transom knee shim? This is where it comes into play. 

I had tapered the very front of the keel, where it butts against the stem. I thought, "how could I possibly mess up a simple 45° cut with a mitre saw?" Well, I did. I wish I had waited & cut this after the keel was installed. In any case, the leftover piece of shim was perfect to make... well... another shim. I just cut it at 45° with my mitre saw, then marked out & cut a "baby shim" for the front of the keel.

Oops. Well, not the end of the world.

"And shim begat baby shim." —Michael 6-9: 18

Now then, time to attach the keel with thickened epoxy:

I clamped my 4-foot level to the keel to keep the aft flat.

Front of the keel, clamped and bolted into place. Here, I've got the shim epoxied and clamped into position on one side. I'll do the other side later.

This is how I clamped the keel firmly into the transom notch. The cross-board is not attached to anything, so it won't get in the way of attaching the transom knee later.

I carefully scraped away the epoxy squeeze-out... especially at the keel-to-transom joint. This is where the knee must fit, as precisely as possible.

Peace, brothers and sisters.

Drilling the keel and transom knee

Soon, it will be time to attach the keel to the frames. 

That will involve bolting the keel to the stem, bolting the transom knee to the transom, and finally — bolting the keel to the transom knee.

This week I ordered the bronze carriage bolts from Glen-L, as well as some more epoxy since I'm almost out. Glen-L is currently in the middle of the company's first-ever move from their original 1953 building into a new facility in San Clemente, CA. That's a pretty big undertaking, so it's understandable if there turns out to be a little delay.

Meanwhile, I've started drilling the holes for those carriage bolts. It sounds simpler than it really is.

Let's take a look at the transom knee first.

In order to drill the holes as straight as possible, and on the centerline, I decided to use my drill press instead of a hand drill. This will also keep the holes at a 90° angle to the knee's flat contact surfaces.

Here's the complication. My drill press has a two-inch travel, which is not enough to go all the way through the knee. Not impossible, but I had to get creative to make this work. 

First, I started with a small drill bit for the pilot hole. In order to keep the hole as clean as possible, I used progressively larger-diameter drill bits to enlarge the hole toward my goal of 1/4". None of these initial drill bits went all the way through.

Finally, it was time to run a 3/16" bit all the way through the knee. The problem was, how? The bit itself was long enough, but the two-inch travel wasn't. 

I drilled the 3/16 as far as it would go. Then, I loosened the chuck and pushed the bit as far upward as I could and tightened it in place temporarily.

Then, I raised the table of the drill press as high as I could & still get the knee under the drill bit. With the knee in place, I loosened the chuck, and pushed the drill bit downward into the hole. I re-tightened the chuck, held the knee firmly in place, and turned the drill press on. 

Thankfully, it didn't bind and spin the knee right out of my hand.

With the drill press running, I finished drilling the hole all the way through the knee. Of course, I had to do all this in reverse in order to move the knee for the next hole. Then, I had to repeat the whole process for the other 3 holes. 

Then, all over again with the 1/4" bit. 

Time-consuming, but it worked. At one point, the drill bit ran into one of the bronze screws holding the knee together. I was concerned that might happen. Fortunately, the drill bit cut right through the softer bronze, and little shavings came flying out of the hole along with the sawdust.

Now, for the other end of the keel.

I started by drawing the centerline on the keel, and lining it up with the centerline of the stem. Then I clamped the entire keel into place, end-to-end.

Since the stem is now permanently attached to Frame 5-1/2, I had no choice but to use a hand drill. The challenge was finding a way to drill straight downward through the centerline so that the hole was centered and straight.

To help with this, I took a block of scrap wood that was roughly square, and close to the same width as the keel. I marked the centerline on this piece, then drilled a pilot hole through it with my drill press. This would be my drilling template.

I aligned the centerline of the template on the centerline of the keel, and clamped it firmly into position. Then, I drilled downward through the template, through the keel, and into the stem.

After I drilled two pilot holes using the template, I removed it. The full length of the keel was still clamped firmly into place.

As I did with the transom knee, I used increasingly larger drill bits in the hand drill until I had 1/4" holes all the way through. The resulting holes weren't perfectly on the centerline on the other side of the stem, but they were close.

The next step was to fit the transom knee.

I clamped it into place, firmly pressed against the keel and the transom.

The fitting was really good against the keel, as well as the bottom frame member of the transom. However...

The fitting against the motor board wasn't so good. Apparently, the motor board is thinner at the top than it is at the bottom, leaving a wedge-shaped gap.

Time, once again, to make another shim.

After a lot of careful sanding on a scrap strip of mahogany, I had a thin and long wedge-shaped shim.

After some meticulous fitting, re-fitting, and more sanding, it fit into the gap nicely. 

The next step will be to trim the shim and epoxy it to the knee.