Keel Sheer and Fairing

Early April was the time to laminate the stem. It was then aligned and supported in position at the bow.


The rabbet/keel offsets were marked on the frames.


After each floor was marked it needed to be leveled and shaped by sanding (faired) to exact height.
Notice the use of the particulate respirator while sanding....


And the appropriate "ladder".....


Not wife approved.......


But "one out of two" safety precautions is better than none. There was some issue of "ladders just not fitting in among the supports" anymore.




A temporary board shows the shape of the keel for fairing.

Quarters are tight, looking from the spraybooth area of the cabinet shop, past the folded lofting table, through the "boat room", toward the true garage.


The port side is pretty tight. Richard is not looking forward to squeezing back there to do the planking....

The transom is in position. Almost all of the beautiful transom is above water line. The placement of the 60 degree angled transom took quite a bit of head scratching and manipulation. The off sets that were plotted needed to be considered with the angle of the transom. The vertical placement and angle were scaled off the drawings.

Its difficult to envision the shape with a full thickness of keel and after planking. Lots of compound sweeps and curves.

Richard placed an extra laminated frame inside the transom to give a wider area to fair across and assist with supporting planking to the transom.

The next step was notching for the sheer. The sheer is basically the line of the boat deck as seen from the side. It is incredibly important in the overall look and feel of the boat. A nicely sweeping sheer helps with the look of a classic boat. Mostly all that can be done upside down and in tight quarters is to scale and measure from DWL to the sheer and get as much curve to it as a board (the sheer clamp) will bend. The bulkheads and frames were notched to accept the sheer clamp.

The batten running the length of the hull near the strongback shows the sheer.

For the next 100 hours Richard got to get very tired of fairing the hull. Fairing is done to bevel and smooth the shape of the frames and bulkheads to flow with the strips that will be epoxied to them. A batten is laid across the frames in a smooth line from stem to stern. All extra wood (high spots) are shaved away with the use of planes or a rasp. This is a very labor intensive and tedious process, but will effect the ease and solidity of the planking. The batten is moved around the hull in different positions, and a fair hull in which planking could be applied in most directions is produced.

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Glued Lapstrake clinker Plank Fairing

Glued-lapstrake is a deservedly popular method for building one-off boats in wood/epoxy - for a number of good reasons. In the case of the amateur and small-time professional builder it gives just about the fastest path to a handsome, round-bilged hull, with the added benefits of being light, strong, attractive given the plank lap lines. Very importantly, the building jig is simple and easy to build.

Ill write more about the particular advantages of the glued-lapstrake building method in another posting, and Ive previously pointed out the way in which a fine entrance combined with the prominant plank laps keeps spray knocked down in a fashion similar to sprayrails.

In the above video, you can see how well the plank laps work at knocking down spray, although the boat (my Periwinkle design) is running in very light winds - but you can clearly see the principle.

To get back to the point, one particular advantage of glued-lapstrake construction is that the building jig need only consist of relatively few, widely-spaced molds or frames, with the plywood planks bridging the gaps between the molds in a fair curve.

Here is a typical glued-lapstrake jig, showing widely spaced molds made from disposable material. In this case the boat was a Francois Vivier-designed Aber which I built for a customer about five years ago.

Plywood is a wonderful material if you can locate good-quality sheets, but one of its virtues is also a liability. Plywood is of almost equal strength in all directions, and is frequently used in much reduced thickness compared with solid timber. The problem is that very occasionally the planks may tend to flatten out between the molds.

Plywood planks going on over widely-spaced frames and molds. This is Periwinkle

Some people put stringers into their molds, but this adds a lot of complexity to what should be a simple set-up, and adds considerably to the cost of the mold. In addition, it makes removing the boat from the mold difficult, especially if the boat has any tumble-home (that is where the sides of the boat curve in towards the centreline of the boat as they get towards the gunwale as frequently seen on "Canadian" canoes for example).

If the building jig is a simple one without stringers, it is easy to access the inside of the boat during construction, and when it comes time to remove the boat from the jig, all one has to do is knock the individual molds out one at a time.

However, there are occasions where the thin planking refuses to lie in a smooth, fair curve - usually just in a few odd places. When I am faced with that situation I use a technique where a stringer, or batten, is applied to the outside  of the hull. It need not even be a full-length batten - just enough length is required to span three or four molds. Temporary plank fasteners are driven through the batten to hold the plank while glue is curing, just as in the rest of the planking job.

Here you can see a temporary batten sitting over a plank lap on the original Periwinkle. There was a little flatness towards the bow (which has been fixed now with a minor alteration to the plans)

Close-up of the batten showing how it sits over the plank lap, and also showing where one of the temporary fasteners has been driven through.

For a job such as this you can usually get away with a single batten, re-used on subsequent planks if and where required. On Periwinkle the batten shown did the entire boat. But it needs to be empasised that the extra fairing is very rarely needed - but it is nice to have the technique available in situations where the ply is a bit too limber, or there is an inaccuracy in the jig.

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