Use wood with tight grain, think of the opposite of Oak it has open grain with deep pores.
Ok now it’s planked. Level the planks with a wood file - sandpaper takes too long.
Next, fill the cracks sparingly with filler. Mask along the seams first. Layout a line of filler and cut off thin lines with an xacto spade bit. Avoid globing filler on the face of the planks, unless a depression needs filling. Pull the tape and sand the fine lines of filler - 220 or 320 should do it.
Now the finish.
Shellac can be used to build up a finish, brush, or Rattle can, it out, sand progressively from say 150, 220, 320. Brush, sand, repeat.
Artists Gesso is not talked about here. It’s an acrylic artists use to prep canvas. Make sure it’s the sandable kind. I’ve airbrush it with a mini spray gun (Iwata RG-3.). Lays out well with a brush.
Make up sample boards, find out what is right for you.
Once you have a smooth hull, ready for the techniques shown above.
Good luck with your ship.