I got the largest/cheapest ship model I could find and it wasn't nearly big enough. I didn't feel like adding it to my collection of unused kits so I "jumboised" her. Not sea worthy, registered, or insurable but she'll get the job done.
Planet XXXXX comprised of many islands of various sizes possesses rich minerals used in tech equipment. The atmospheric conditions are not suitable for regular air transport and in the grimdark, boats still move stuff the cheapest. Ships are used to ferry supplies and move mineral cargoes from mines on the smaller islands to larger islands which serve as hubs for off planet transfer via bulk lifters. Surface freighters are limited in size due to dramatic shoaling and the need to be able to maneuver around hazards to navigation.