once you have the finish smooth, (trust us on this), you will have a better finish, in fact it looks better now than it did with those faux ribs that you tried. spray the hull in 3 or 4 coats of "red oxide" colour primer, this colour is practically the same colour as what they use for antifouling paint on full size ships.
then lay on your red colour, at a guess, a red similar to Deutsche Bahn red will suit it. to get the waterline level, lay the ship on a flat surface, if you have some lego blocks wooden profiles, or dead batteries, lay them down alongside the keel if your boat is not flat bottomed, pushing them inwards until your boat is level, however if she is flat bottomed, just lay ot on the bench.
Measure up the hull, 50mm, 75mm or what ever it is meant to be on a block of waste timber, say 50mm x 50mm x 100mm and DRILL a hole through it horizontal, and insert a sharp pencil through it then tape it in place. run the pencil down the hull from bow to stern. With that done, get some masking tape and news paper. tape the masking tape half overlap to the news print, so half of the tape is holding the news paper, and use that. holding the tape at the bow, gently pull it towards the hull, keeping it to the waterline you marked. once this is done, mask up the upper deck and spray. Because your boat has a slight twist in it, I suggest you do the waterline 5 to 10mm lower than it should be so its not so visable when on display, but ballast to how she SHOULD be, only drawback will she'll look deeper than she really is
once it starts to look like its going to dry, remove the tape. This is how I did ALL my dual colour hulls