1:48 is unusual territory for submarines. It is twice the linear size of 1:72, so a Type VIIC comes out close to a metre and a half of hull — which is why the scale stays a specialist corner rather than a mainstream choice. What you gain is surface: plating joints, free-flood slots and hatch rims are all large enough to work with a brush rather than a pin, and the long hull seam has to be dealt with properly because at this size nothing hides it.
If the footprint puts you off, 1:72 submarine kits give the same level of moulded detail in a hull you can still shelve, and that is where most upgrade sets are aimed. For railings, periscopes and resin compartments see submarine detail sets, and the complete scale range is listed under submarine model kits.
