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Stitch and Glue 101 - Draw the Panels

Cutting the panels:

Let’s start by drawing the shape of the panels on the plywood, one side panel first.

How to draw a panel (side) on the plywood:

Blueprints or patterns?
Blueprints can be intimidating for first time builders and many assume that full size patterns will be easier. This is not true: full size patterns lines are difficult to transfer to plywood and patterns are inaccurate. Patterns are difficult to handle and position precisely. With humidity and temperature variations, the paper patterns shrink and stretch up to 2% and this means a few inches in the case of the FL12.
Full size patterns and dimensions are provided with most of our small boat plans. You choose the method you prefer but in this file, we will explain how to use dimensions.

Transferring plans dimensions to the plywood is easy when done one step at a time.

We will work not only one panel or one curve at a time but one point at a time.

To draw curves, we will mark points and then join them with a batten or PVC pipe. This method produces accurate and fair curves.

Plywood layout
Let’s look at the plans page that shows the nesting of the panels on the plywood:

The drawing shows 2 side panels and some other parts of the boat on 2 standard sheets of plywood.

The side panel is longer than one sheet of plywood. It is made of two pieces joined with a butt block. We will line up two sheets lengthwise to draw the panel.

As you can see, one side of the panel is straight and coincides with the edge of the plywood sheet. That straight line will become the nice sheer curve when bent.


(some boat part names used in this file)

Using dimensions ? Mark Points
The panels drawing shows the dimensions of the side panel:

The two ends are straight lines: we will mark the corners and draw a line between the points. The chine side is slightly curved. To draw that curve, we will mark points and join them with a smooth curve. To locate the points, we will draw vertical lines every 24” and measure a distance from the lower edge of the plywood sheet.

See the text 24” Typ., it means typical dimensions every 24”. Unless another distance is shown, the distance between those lines is 24”.

In this case, the typical vertical lines start in the middle, between the two plywood sheets.
We will start by drawing those vertical lines.
Remember, take it one step at a time. In this case, let’s just draw those lines, nothing else.

Mark a point every 24” along the edge of the plywood.
We don’t need a square to draw the vertical lines, let’s use the plywood sheets.

Slide one sheet of plywood over the other, keep the edges lined up, draw a line along the short edge. All your vertical lines will be perfectly square.

This is how it looks with all the lines marked.

Next step. Let’s put our plywood sheets together to draw the panel.

Along each vertical line we will mark the points that outline the shape of the side panel.
We start with the points for the curved side, the chine edge of the panel.
The distances from the edge are clearly marked.

In this case, the first point is at 16” from the edge, the next one at 14-3/4”.

Draw all the points.

The ends of the line are a little bit different.
The tip of the bow and transom are not on a typical line.

The plans show how far they are lengthwise. In this case, you measure 8” from the previous typical line. Beware, the dimensions may be different on your plan, this is just an example.

Draw a vertical line at that distance.
Along that new line at 8”, we show the vertical distance (offset) along that line: 12-5/8”.
Measure and mark the location of that point. It is the end of the chine curve, a corner of the transom.

To draw the transom edge of the side panel, we need a second point, the end of the sheer side.
That point, along the edge of the plywood is also not on a typical 24” line.
The plans show how far that point is from the last typical line.
Mark the end of the sheer line.
Now, join the two end points and you have the transom side.

Proceed the same way at the bow: draw a vertical line, mark a point and join your two points. This is your bow edge.

Now we have three of the sides: the two ends and the sheer edge. Next, we will draw the curved side of the panel, the chine side.
We have the two ends and marked all the points in between. All what is left to do is to draw a nice curve. We will do that with a few nails and a batten.
Drive a nail in the plywood at each point of that line.

Let’s start at the bow:

How to Draw a Fair Curve

With a nail at each point, use a PVC pipe to draw a nice curve.
Note how we use weights to keep the pipe in place.
Ideally, we should use a longer pipe.

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