Tuesday, January 28, 2014

I couldn't resist...

I managed to get the bottom plank cut out on Monday night, and now that the base shape has been established, I wanted to see what some of the bulkheads and stem look like dry fit. 

Before I actually get to fitting them, I still need to finish the base ladder frame. There will be 9 stations of varying elevations fixed to the frame that will provide the "rocker" or bend to the garboard plank. Once these are installed, I'll glass the inside of the plank, fasten the keelson, and then begin permanently fitting the centerboard case and various bulkheads. From here on out, it will start to look more and more like a boat. 

As many people have written before me, there are myriad details to this project. It's one of those things that if you actually made a list of everything that needs to be done to complete this boat, you might never undertake the project. I'm a bit impatient by nature, and I'm constantly fighting a great temptation to jump ahead and perhaps gloss over details. But I know from my limited experience that the more detail I pay attention to now, the less work I make for myself later on. I find myself having to think several steps ahead of where I'm working. For instance, in order to save myself a massive headache later, I need to fiberglass the inside bottom of the boat now, when there's nothing in the way rather than wait until I have to work around 8 bulkheads and a transom. Likewise, I want to epoxy encapsulate each of the bulkheads now before installing them, as it will be easier to sand and clean up when I don't have to reach round fixed installed parts and stringers. It's something that wakes me up at 3 in the morning sometimes as I come up with little details that I need to attend to before moving to the next step. 

So far, though, I'm having a blast, and greatly increasing my woodworking skills every day.

Oh yes...one big AHA moment yesterday. I splurged on a compact laminate/trim router. Cool little tool, but I underestimated its power. After turning it on, I applied it to a piece of wood to test it out and it jumped right out of my hand. Not once but twice! Luckily it didn't hit me or cause any damage.  But the thought of a router cut in my leg or hand or worse is a good reminder to respect ones tools and make sure to use BOTH HANDS on routers. Even the small ones. 
Starting to take shape

You can almost imagine the shape of the boat!

Making the centerboard

One of the first things I'll have to do once I've finished assembling the building frame and laying out the bottom (garboard) plank, is cut a hole for, and set up the centerboard. For those who aren't sailors, the centerboard is Navigator's primary "keel". It's essentially a retractable wing that provides lateral resistance below the waterline for wind pressure on the sails above the waterline. When wind fills the sails, from the side of the boat, the centerboard will stop the boat from slipping sideways through the water, and channel the energy by providing a hydraulic version of "lift", and help the boat move forward through the water. 

So it's a critical part of the construction. I've chosen to make the centerboard out of a laminated pine blank, coat it in epoxy and sheath it in fiberglass.  It has a very specific shape defined by something called a NACA profile. I made a template out of scrap plywood, like Robert Dieterich did for his Annie build. See his blog for photos. This was used to channel out the general shape of the foil. I then used power and hand planes to shape the board down to the router cut-lines. 

Once the board is finished, it will be "housed" in the centerboard trunk, which is exactly what it sounds like: a box (waterproof) that the board can be retracted into for downwind sailing, or beaching and trailering the boat. 
Laminating the centerboard blank
This is a full-size template for the NACA foil shape. Effectively a horizontal cross-section of what the centerboard should look like.The finished side will be the smaller foil in the inside right. The rectangle is the blank shape. The larger outline is the offset for the router template I made to guide the initial shaping/carving of the blank.

The roughed out centerboard. You can see the pivot hole a the bottom (top) of the board. The rounded rectangular protrusion will be where the up-haul pennant shackle gets attached for raising and lowering the board during sailing.

Roughed out board

Carving out the pennant shackle attachment point
Back side shot of the same area

Front top view of the board. You can see the blade shape emerging.

Cutting and shaping the sides of the centerboard trunk.

The "hump" at the front end of the case accommodates the radius of the pivoting board and holds the elevated pennant shackle block.

Scarfing the garboard plank

It's been a while since my last post, but it doesn't mean that I haven't been busy. Lots of progress in the past few weeks. I'll put up a few posts with pictures to give you an idea.

By the way..."scarfing the garboard plank" is just nautical speak for "tapering and gluing the bottom of the boat together".

Now that all the main pieces of the hull structure are finished, I built the ladder frame and laid out the bottom plank(s). Because the boat is 15 ft long, I have to join two pieces of 9mm ply. Lots of ways to do this, I guess, but the general consensus among Navigator builders is to do an epoxied scarf.

Following others, I went with a 8:1 ratio. So a 9mm plank will have a taper that is 72mm long. In order to do this, I stacked both pieces offset by 72mm. I scribed a reference line across both sheets of ply, and hand-planed them down. Sounds daunting, but really isn't too bad. The layers of ply actually end up providing a pretty decent reference point, as you can see from the pics. The idea is try to get the lines as straight and parallel as possible. When this is done, flip one sheet over. Line them up, and glue with epoxy. Voilá! a 16' sheet of ply of uniform thickness.

Next up...work on the centerboard and centerboard trunk.

Initial planing work

Here you can see the individual layers of ply showing through the tapered planing
Used a piece of lumber as a guide for the plane along the scribed reference line so as not to plane too much
Getting close
Gluing up the scarf. That's a thickness planer being used as a weight to hold down the improvised wooden bar clamp!

Saturday, January 4, 2014


Or more accurately, epoxy.  Ugh. What a sticky mess. Last year, when I built my CLC Tandem Wherry (see the 'Andiamo' pix), I got my first taste of working with this miracle stuff. It's very intimidating at first, but it turns out to be not nearly so daunting once you get into it. There are lots of ways you can use it:  It can become a waterproof coating, glue, a bonding resin for fiberglass or other strengthening composites like kevlar or carbon fiber, a strength-providing fillet, filler for mistakes and gaps, and it can even be molded into structural parts.

In this case, I'm using it as a super strong glue. After cutting all my bulkheads and doublers, it's time to start gluing them up. You mix small batches of resin and hardener, in carefully measured amounts. You add some filler to thicken it up to the desired consistency, and get to work. The stuff can get pretty goopy and drippy, and once it cures, it's crazy hard to sand and smooth.

So last year I learned that it's much easier to clean up epoxy while it's still wet. I downloaded the Russell Brown's booklet Epoxy Basics, which gives some great tips on how to really do this work in a craftsmanlike way. I'm making an effort to put his techniques to use.

Another day or two of this procedure and I'll be ready to start setting up the building frame, garboard, keelson, and bottom stringers. It's by no means the end of epoxying...I should become an expert at it by the time this boat is done. More in posts to follow...

Meantime, it's Antarctic weather here in Wisconsin this week, so what better way to spend the time than working in a nicely heated garage on an enjoyable project!

Bulkhead #4

Pleased with the hole cutouts. I used a plunge router with a circle jig to cut two holes and then connected with my jigsaw.

You can never have too many clamps. I ran out tonight.
An example of cleaning up a glue joint before it sets. See...no drips or clumps.

I made an epoxy mess out of the stem, and paid the price sanding and scraping with a heat gun later.