Cutting the Stem

After finding a design, revising the design, revising the design again, and then throwing out the design and starting from scratch; it is finally time to start cutting the wood for the dinghy construction!

While the dinghy design is still not finalized, there are two parts of the dinghy that are, the keel and the stem. So in the interest of getting it built, these two pieces are going to be cut.

The height of the stem will be 18 inches, and it will be a plumb bow. Knowing this, I decided to cut the stem out of the pieces of Douglas Fir, also called Oregon Pine, that I have been drying for the past few months. The stem will be subjected to a lot of stress and needs to be a very strong component.

For these reasons, I selected a board that has a very tight ring structure with diagonal rings on the board. Diagonal rings are called quarter sawn, and these boards will not warp. They are very dimensionally stable and will expand and contract evenly across the board. This will result in a stem that will swell and contract evenly and hold the bow of the boat together as we cruise.

Quarter sawn lumber is very expensive, so the cheaper alternative is to comb through the available lumber and find a piece of flat sawn lumber that crosses the center of the tree. This board is flat sawn but when cut in half, the end result will be quarter sawn.

Looking at half the board, the rings run diagonal across the board in quarter sawn fashion. 

The stem will end up being 18 inches long, so I need to find two 18 inch sections in this board that are clear and clean of knots. This strip here is 47 inches long, and has one knot in it near the bottom, but outside of the 18 inch sections needed. The knot on the midline will be cut out when the stem is shaped.

By cutting the section out, the boards can be set with grain opposing itself which will provide even more structural integrity.

The rip fence was installed to guide the saw and make sure the cut is straight and even. The wood was removed from the board and then cut in half. Each half is set so that the grain will point forward and towards the middle. This will provide a very secure surface for the planks to attach with the screws traversing the wood nearly perpendicular to the grain.

After cleaning up the boards on the jointer, the pieces are beginning to look a lot better. The grain will oppose each other and ensure that no movement happens in this piece.

A very liberal coating of glue was applied to the boards and they were set up in clamps for 24 hours to allow them to cure. This will glue the halves of the stem together very securely. During the construction of the dinghy, screws will be placed through the stem, further tying the two halves together in a permanent manner.

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