Here's a 1/300 model Fairmile C motor gunboat (MGB) used by the Royal Navy in WWII for coastal naval wargaming. It is mostly complete now. *EDIT* I've finally added guns - a power-operated 2-pounder semi-automatic for the bow, and a manual 2-pdr rolls gun for the stern.
Print it at between 0.1mm and 0.15mm layer height on an FDM filament printer. The guns will need support. Printing them with the barrels pointing upwards may help, but is less sturdy.