Here's one for the Scratch Builder of Hulls using Paper Models for patterns!
Now, Paper Models in and of themselves go together way different than Plastic for sure. But you still have to start with the Deck and Hull Pieces. When doing these out of plastic there's something to consider in the Hull's Stern and Bow area that needs addressing. When you cut your .010 or .020 sheets for the Stern shape and Bow Flares you must be aware, it is an Angled Butt Joint! or Joints. That's fine as long as you get them right! This is important for the new step I have devised, for smoothing them out to give them less a paper feel!
When you carefully shape and glue these places you will want to do the one thing the Paper model is hard pressed to do. You need to make, remember, a curve outward at the bow from Fore to Aft and from Water to Deck! So work your piece over a Hot Spoon in hot water and then hit it with cold to lock the shape in. Now back aft you will have some relief cuts to allow the stern shape. You must curve these to fit well the same way, from the outside of the ship to the centerline edges. One of the main things is this. It won't seem like much. Leave about tha thickness of a pencil line showing on both sides of the relief Cut. This will allow you to really get the right curve in the panels to align the edges and create those curves, Glue and keep to the centerline of the ship. here's a little note for ease of assembly.
On all ships prior (1958-1988) to the module type construction used now, they had Doubler Plates specially shaped to close up both ends of the ship. Some were flush some weren't. For the flush ones you'll have to create stringers lengthwise in the bow and stern to mount them. Or the other way is to Overlay .010 right along the centerline then putty the edge and blend, Sanding gently, and paint with, Clear flat. Or use .020 to represent those ships that had those centerline plates standing proud! it won't create a big ledge because as the glue dries you'll put just a wee bit more on there to lock down the edges. In the softened state the ledge between plates will be less pronounced and more scale looking.
Oh! for the purists among you. Many can be had as Waterline only. There are some companies that do not include bottoms. WilhelmShaven usually includes a Deck and Waterline Plate with the Keel up construction. What you do then is this. After the hull is done with the frames and Keels in place(Some do Not have keels either! Sit the ship on a piece of Construction Paper. Do NOT, I repeat, Do NOT. create your bottom plate out of the piece that would be your bottom but rather the paper pattern. You may have to refine the curve between frames a little. So also the thing about leaving a pencil line at the bottom applies too. This way you can slip the bottom plate in the hull and it will hide from view. If you choose make the pencil line Thicker than one line.Then you can use a thicker bottom plate (.030?)if you wish!
On Wilhelmshaven kits, their Centerline plate(vertical) also includes the side profile for the Deckhouse! DO NOT cut this off!