There are inner and outer.
Learning the terms first? Good.
The stems make the curve of the bow and stern. The planks, strips, or whatever normally fasten to the inner one. The outter one covers or blends into the planks or strips to give the bow and stern smooth transition.
Happy Paddl’n er Build’n!
the vertical piece at the front (bow)
or front edge of a boat is the stem.
Such a simple concept
but really hard to explain in text.
Basically they are pieces of wood (or laminations) that help to define and add strength to the bow and stern of the boat.
Imagine you are building a strip-build boat.
At the bow and stearn, the strips from the left and the right need to come together at the correct location to define the shape of the bow or stearn. To get this to happen, first you need bow and stearn forms.
But, the forms have thickness. If you bring the right strip to the right side of the form, and the left strip to the left side, the two strips don’t touch.
So, grind down the forms to a knife edge. Now the strips touch, but only at the corners.
Bring the knife edge back a little more, and some planing of the ends of the strips, and the strips now fit together nicely. But, there is relatively little glue area to hold them together.
Now, instead of making the knife edge on the form itself, cut back about and inch and a half from the form and replace it with a piece of wood (or lamination) of the same shape, then put your knife edge on that piece. Now you have a nice large area to glue the strips to. The piece stays in the boat when it’s done. That’s an inner stem.
Outer steam goes over the end of the compeated bow and stearn to cover all the butt ends of the individual strips.