In a medium bowl, whisk together the sugar, salt, and egg until the mixture becomes pale in color and has increased in volume. Switch to a wooden spoon and mix in the orange juice, zest, and olive oil.
Then mix in the flour ½ cup at a time until you have incorporated 1 ½ cups of flour. Then add 1-3 more tablespoons of flour until a dough forms. It should be soft but not overly sticky. Use your hands to work the dough until smooth.
Cover the dough and let it rest at room temperature for 30 minutes.
After the dough has rested, preheat the oven to 350°F and line a baking tray with parchment paper.
Remove the dough from the bowl and divide into two and then in two again. Then cut each of the four portions into three even sections. Finally, divide each piece in half one more time for a total of 24 pieces.
Take one of the pieces and roll it out to about 3 inches in length, pinch the ends vertically, and place on the baking sheet. Repeat this shaping process with every piece. When they are all shaped, cut a slit lengthwise down the boat.
Brush each navette with milk and then place them in the oven to bake for 20 minutes at 350℉, flipping them over halfway through. Remove them from the oven, flip them back over, and allow them to cool completely before serving.