Transom and transom fore face

With the profile, half-breadth and body plan completed, it’s time to move on to plotting the true shape of transom which is the aft frame of the boat. Now as this is a raked transom - not plumb - (meaning it’s not at a right angle) the body plan will not have the true shape nor size for transom.

Body plan aft view. Neither the shape nor size of the transom (marked asstation #9) are true in this view.

In order to plot the true shape of the transom let’s draw all lines that intersect the transom in the profile view (incl. sheer, waterlines, chine, rabbet, buttocklines) at a right angle to the transom. These lines should be at least the half-width of the longest measure of the transom (+ a little extra). As with the boat’s own half-breadth also the transom is plotted also half only (because the other half is a reflection of the drawn part) but it’s a good idea to leave more extra space. To make it less confusing these lines are usually drawn aft the transom in the profile view. Since I had not enough space aft on the profile view paper roll but just enough fore of the transom I went out and bought yet another color marker pen (black this time) and plotted it there making use of the trammel.

With the horizontal (right-angled to the transom face) grid set up I took out the tick-stick for center-and-buttocklines locations and laid them out right-angled to the horizontals leaving just enough space between the profile transom view and the transom expansion centerline.

Since this boat’s transom shape has actually only three significant measurements (for sheer, chine and rabbet) as the lines connecting them are straight, I took a fresh tick stick and ticked the locations for sheer, chine and rabbet from the body plan using the centerline as the reference. And then transferred these to the transom expansion grid (using it’s centerline as the reference) - sheer-mark to the sheer horizontal, chine-mark to the chine horizontal and rabbet to the rabbet horizontal. And then simply connect the dots with a straight-edge (no curves necessary).

The plans I’m using don’t specify the actual deck height so for the transom curve I decided to go with the classic 4in in 8ft. But since this is currently only a single curve then most probably this might change after some more planning and laying out the other frames. Or maybe not. We’ll see. Anyway, the transom curve was drawn using the draughtsman’s method.

With the transom expansion completed, all that’s left to do is the transom fore face. These lines will show the shape and size of the transom on the inside of the boat. According to the original plans:

The transom is made out of 1 3/4 x 8 inch boards secured on inner surfaces with 1 3/4 x 4 inch frames.

This converts to 4.5 cm * 2 = 9 cm thickness for the transom.

The transom fore face plotting starts with drawing a line to the profile view parallel and fore of the transom (aft face) at a distance of the transom thickness. Next, as with the transom expansion, at a right angle extend all intersecting waterlines, sheer, chine, rabbet and buttocklines. Keep in mind that with an aft-raked transom these lines will be parallel to but below the same lines for the transom aft face (the expansion drawing done earlier).

The same measurements (sheer, chine, rabbetline) as for the aft face need to be plotted for the fore face. On a clean tick-stick, I marked perpendicular to stationline #9 the point of intersection for the sheer and the transom thickness line. Then using station #9 as a reference transferred this tick to the half-breadth centerline and B2. Now the transom fore face intersects the sheer at the location where a line drawn through these points intersects the sheer in the half-breadth view. Marked this to the tick-stick using the centerline as a reference and then transferred this to the transom expansion but on to the sheer-horizontal that represents the sheer and transom intersection. Did the same for chine and rabbet (and a few mis-measurements later) arrived at this plot.

Completed transom expansion half-breadth including fore face measures (in black),aft profile (in blue) and profile buttocklines (red), lofting grid is in brown.Note the many mis-drawings because of too little labels at measuredlocations during batten-curving or mislabeling for not seeing the wholepicture in one go.

But anyway. The bulk of plans is now complete. The work that lays in front now is doing keel cross-sections and preparing a bevel-board. And then hopefully I can concentrate on drawing up full size plans for all frames, breast hook, engine bed, transom knees and stem pieces.