The Keel

What the %&! is a Keel? (and why do I need one)...

Answer:  the longitudinal structure along the center line at the bottom of a vessel's hull, on which the rest of the hull is built, in some vessels extended downward as a blade or ridge to increase stability.
Okay, that's all for now... Good night everybody...

Seriously, a keel adds stability and in this flat bottomed design it adds even more.  It should improve the tracking of the boat so it isn't as prone to slip sideways in the water and will help the pounding that can occur in choppy water.  The designer proposed a box keel.

Keel shown in yellow... Grey man contemplating why his toes turn up.

That is a hollow "box" attached to the bottom of the boat.  A box keel doesn't add any weight down low (which we think will add to stability) and seems a place that could be subjected to water infiltration that we would not be able to inspect.  Instead we opted to make it a solid timber, glued, screwed and bolted to the bottom. We also liked the idea that if ever grounded it would be our first line of defense, and a seriously substantial one. So, lets build this thing.

Milling and Material...
Again, we turn to our familiar, favorite southern wood, Yellow Pine.  Yep, they are all around us and we love spreading their needles around our holly but did you know its a "heckuva" boat wood?

Establishing a center line

Hard, heavy and rot resistant; perfect for a keel.  The bottom is curved and we didn't feel like finding a timber big enough and long enough to suit and end up at the surgeons office scheduling a "repair".  The same frame material was readily available in 12" widths  and we knew that we could probably horse a 1" thick board down into that rockered bottom's shape.  We only milled the 12' boards enough to even up the thickness and width, leaving as much meat as possible.


Cutting and Laminating...

Taper on Masonite.

First Layer

There is one more step before we attach the keel and that is to shape the fore and aft ends (gonna start using nautical terms now).  The fore end of the keel must butt into the stem at an angle and tapers down to the stem's width.  To accomplish this we measured back 3' from the end of the pattern and sprung a spline that tapered a gentle curve from a 12" width to the stem's 4" width on a piece of Masonite.  We then cut that curve with a circular saw and transferred it on each side of a center-line, then cut the pine boards to match the pattern. To laminate, we used a combination of epoxy glue thickened with milled fiber and silica and 2" 316 stainless screws.  We also staggered the joints just starting from the aft end on one layer and the fore end the next.  Both fore and aft ends get the same taper.  This process repeated itself for 5 layers with a final keel measuring 5" x 11".

5 Layers High

Final shaping...

This shows the stem but note
the keel angle.  Stem is next.
Can't wait huh?

Okay, almost ready to do something else but one last little bit of work.  We need to give this keel some shape. Lets start with the stem end.  Simple enough, just need to transfer the same stem angle up keel.  Cutting was roughed in with a reciprocating saw and final shaped with a planer and belt sander.  Constantly checking with a straight edge.
Now, turn 180 degrees and walk to the back of the boat.  Good, let's shape the stern end of the keel.  This gets a little different shape and when conversing with the boat's designer, Karl Stambaugh, he suggested a rounded, tapered bulb to clean the water as it rolled off and reduce turbulence at the outboard prop.











Here's the steps.

1. Taper at a 45 degree angle and trim with a saw (again for me reciprocating).

Mark the angle

Trim off but for God's sake get closer than I did.

2. Belt sand to the line (get closer than me, too danged much sanding here).

Freehand an arc

3. Round a line and belt sand to that line. This just takes a little time and I finished off with a 6" orbital.

Well that's about it for the keel.  We ran a 3/4" round over router bit around the edge and it still needs a fillet of epoxy around the base to help the polyester cloth to lay smooth and the whole thing needs filling and smoothing but more on that later. Stem to soon follow.

BTW, in real time as I'm posting this we are in the final stages of sanding in preparation of glassing the hull. The stem and transom are done and a lot of shaping is finished. We'll follow up with successive posts to catch us up rapidly so check back every few days.  Thanks for looking!