Boating Plan: bottom

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Completion of starboard bottom

June is upon us once again. I have now been working on my Glen-L Utility for just over two years. A good two years it’s been, too. The little boat and I have both come a long way, in many regards.

I’ve just completed planking the full length of the starboard bottom. It’s neat to think that a year ago, I was installing the sheers.

I should be able to start dry-fitting the forward port bottom this week. My goal is to have the boat fully-planked by the end of the month.

As always, time will tell...

This is what the boat looked like 1 year ago. The sheers had just been installed, and fairing had not yet begun.

Initial fitting of the butt blocks.

Butt blocks dry-fit with screws.

Butt blocks epoxied, screwed & clamped into place. Putty knife at the ready.

Epoxy squeeze-out like this will create a fitting nightmare if you let it cure this way.

Thats what the putty knife is for. Scrape it away before it cures.

Aft section battens & butt blocks drilled & ready-to-go.

Aft panel drilled & ready-to-go.

Starboard bottom, fully planked.

The Utility New motor First bottom panel cut

This first half of April has seen some progress on the Utility project, although not much that is visible on the actual boat itself. I ordered a new Nissan 8hp motor from onlineoutboards.com. The motor arrived very promptly... and I promptly realized I’d never operated a tiller-controlled boat before.

New 8hp Nissan Marine outboard

So, the kids and I fixed that by taking a weekend getaway at a nearby lake. I rented a 14 ft Jon boat fitted with a 9.9 hp Yamaha, and we ventured out on the water. There really is a lot to be said for the simple Jon boat. They may not be the prettiest things on the water, but it’s hard to imagine a more versatile boat in that size.

In any case, our little aluminum Jon boat was by no means a rocket on the water, but it did what it was supposed to. The Utility will have a shorter, and more streamlined hull, although somewhat heavier. I imagine performance with its 8hp motor will be similar to the 14’ Jon boat with the 9.9 Yamaha. Time will tell.

Over Easter weekend, I began the break-in period for the Nissan motor. The first two phases were to let it run at idle for 10 minutes, then to run at <50% throttle for two hours. That’s done. The next phase is to let it run at <75% throttle.

On the boat framework, I have faired down the side planking on the starboard side. I have not yet tried to fill in any of the low spots, or “hollows”, along the chine. Instead, I decided to go ahead and cut the panels for the bottom planking by cutting one sheet of Meranti in half lengthwise.

My plan is to begin dry-fitting the bottom panel into place, and to use that as a gauge to determine just how much I’ll need to fill in along the chine. It is possible that any gaps will be minor enough that thickened epoxy will do the job adequately.

Rough placement of the first bottom panel

Bottom panels complete

Here are the two bottom panels taped and cut to shape. I feel as if I am in the groove now and can get the side panels out a little quicker now.

I did experiment with a number of release films for the fiberglass epoxy tape joints.

1. 6 mm plastic - was hard to get flat and fair. wrinkles developed easily

2. packing tape - harder to apply, but left a relatively smooth controllable surface.

3. wax paper - best looking joint, but waxy residue must be cleaned. I was warned by a more experienced builder that the wax could separate out of the paper, leaving a ghastly mess to clean up. I did experience a little of this in the top joint, when I tried to remove the paper prior to full cure.

Bottom line - will stick with the 6 mm plastic. a little extra filling and sanding is part of the project.

Incremental progress on the first bottom plank

So, cautiously and methodically, I have continued fastening down the first panel for the bottom planking.

Using a 4-foot ruler as a straight edge, I drew reference lines on the plywood to show placement of the floor battens. That made it much easier to mark the places to drill holes & drive screws. Marking the chines for screw placement has not been so easy. I’ve had to cut away enough overhanging material so that I can use my marking gauge — the same spring clip & duct tape arrangement I used on the side planking. I used the Porter Cable multi-tool saw to cut away plywood as I worked my way forward... cutting new plywood washers as I went.

Bottom panel, before much extraneous material was removed.

Looking forward, you can see the panel begin to curve and twist.

Reference lines for the battens helped greatly with screw placement.

Near the forward frame, the plywood begins to curve and twist considerably. At times, it seemed like I just couldn’t bend it any more without breaking it. I followed the technique outlined in Boatbuilding With Plywood, and cut away as much extraneous material as I could, while still leaving myself adequate material to work with. It is amazing how much easier plywood will bend when excess material is cut away.

Here, a good bit of material has been removed from the panel. It became much easier to bend.

For now, my progress has stopped at the forward frame. I’m just inches away from the transition joint. To mark the approximate cut line up forward, I coated the corner of the side planking with a lumber crayon & bumped the bottom planking panel against it to transfer the mark. It worked reasonably well. Soon, I’ll remove the bottom panel, cut near this line, and re-attach the panel for further fitting.

The transferred line on the inside of the panel should help greatly when I remove the panel & trim it down further.

Once this panel is cut to shape, I’ll be able to use it as a template for the other panel.

Bottom port forward is dry fit

On Fathers Day, I finally completed dry-fitting the bottom planking on the forward port side of the boat. Im very happy about that.

Port bottom planking, dry-fit with screws and washers.

The fitting started off wonderfully at the aft end, where the planking joins along the centerline of the keel. By the time I finished at the bow, however, there were some spots where the fitting was not as good as Id hoped. These spots can be filled with thickened epoxy, of course. Still, I wish the fitting had been better.

About midway along the keel, there is an open seam approximately 18 inches long, and about 5/32" at its widest point. There was also supposed to have been a transition joint just forward of the end of the keel. I did not pre-plan for this, and as a result, I kind of messed it up a little bit.

5/32" gap along the centerline of the keel.

The missed transition joint.

In retrospect, I think both of these mistakes could have been avoided if I had overlapped the planking along the centerline of the keel, and trimmed the whole length to fit as I went.

There is another small gap between the bottom planking and the side planking at the stem.

Another small gap up forward.

My plan is to use epoxy thickened with mahogany sawdust (ie: Wood Flour) when I glue this panel on. From what Ive encountered so far, this mixture seems to absorb impact better than epoxy thickened with #2 silica (which seems more brittle). The thickened mixture will fill in these gaps, and I believe that in the end it will all be just fine.

Completion of dry fitting starboard bottom

With the first forward panel dry-fit, and the Raptor staples sanded off the transom, the next tasks ahead of me were:

Decide how to finish the transom.

Fit one of the aft panels.

Drill & screw the remaining holes in the forward panel.

I had originally planned to stain the transom before fiberglassing it. This is mainly because I felt that Meranti had too much of a dull brown look to it. I wanted the bright finish to have a good bit of red. I was having a hard time finding the right type of stain to do what I wanted. I was also beginning to get the idea that staining and finishing plywood is a bit different than staining and finishing solid stock. Another boatbuilder, with far more knowledge about woodworking than I have, convinced me to at least try a large sample swatch of epoxy over some un-stained Meranti to see what I thought. I did, and was happy enough with the result that I decided to abandon the idea of staining it first.

Un-stained Meranti with a layer of SilverTip epoxy.

Un-stained Meranti with a layer of SilverTip epoxy.

Next came fitting one of the aft bottom panels. Compared to the front, this was quick and easy. Since the aft end of the forward panel is so far back on the boat, the aft panels only needed to be 33 inches long. I cut 33 inches off of one of the full-size sheets of plywood, then cut that in half. I used the factory-cut straight edges to align the panel on the keel’s centerline and to butt up against the forward panel. It fit together very well & I started placing screws every 6 inches, just like the forward panel.

Aft starboard bottom panel fitted into position.

With both pieces fit, and the overhanging edges trimmed down considerably, I looked for any humps or hollows along the surface. Fortunately, I did not see any that I could discern with the naked eye. So, I decided not to shim the chine any on this side.

Thankfully, I did not see any visible humps or hollows on this side.

Lastly, I placed all the remaining screws in the forward panel. Now, there are screws located every 3 inches, so I will not have to worry about trying to do that at the same time as I epoxy the panel down permanently.

The next step will be to remove the forward panel and use it as a template to cut the forward port panel.

All the bottom planking is fitted However

All the bottom planking is finally fitted.

Two steps forward and one step back. Technically, that is still progress. That’s also the current situation with the Utility as I try to finish up the bottom planking.

In a nutshell, the panels are all fitted, but there is a little more fairing work to be done. Back in March, I mentioned in a post that there appeared to be a low spot on the port chine. With the planking on, I can see that this problem is compounded by a second one: there is also a high point on frame #1.

These two photos show the "hook," or low spot in the planking caused by a high point on frame #1 and a low spot in the chine.

So, what needs to be done now?

I’ll have to remove the panels, and sand down that high point on the frame. I’ll also have to add some more wood to the chine to build up the low area. Then the panels can go back on to re-check the fitting.

Aside from that issue, there has been other progress. I cut away part of the sole support on the transom to make room for a drain tube. I have not decided yet for certain if I will add a drain tube or not. However, if I do, part of the sole support would need to be removed. That is much more easily done before the bottom planking is attached permanently. I cut away a section 1-3/4" wide, next to the port transom knee. That should allow enough room to install a 1" drain tube. A coping saw and a couple of chisels handled the job nicely.

1-3/4" of the sole support on the transom cut away to make room for a drain tube.

Seat risers

This design is done up butterfly style. Where the two halves of the boat are stacked, stitched together with copper wire, then unfolded to make a three dimensional shape.

The seat stringers should have been tapered prior to glassing the panels together. But, I was in a hurry. the result was some cracking on the forward upper panel. I will need to reinforce with glass when done. the whole assembly is in the garage waiting to go three dimensional.

Butt blocks on the port bottom

Not a lot of visible progress since the last post... mostly sanding throughout the last week. However, I did get the backing blocks attached for the last butt joint, where the two bottom panels on the port side will meet. Here are a few photos: