That's basically what the factory does when they build johnboats. The hull is made out of 2 seperate pieces for the starboard and port sides, and the 2 pieces are joined in the center, with a center strake, which is welded all the way down each side.
However, this is also the first place that corrosion will attack a johnboat, as the heat from welding changes the properties of the aluminum, making it more susceptible to corrosion (kinda like where ever you weld or heat a piece of steel, that is the first place it's going to rust)
But I have repaired a few johnboats with the center strake completely gone (including my own 16 foot Dura Craft) by using a piece of 3/16" aluminum angle, the length of the boat, placed over the damaged strake, and welded using a spoolgun and ER5356 .030" aluminum wire.