Scum swarms are flotillas of ships that travel together on a nomadic path across the solar system. These fleets are composed of numerous diverse spacecraft, many of them repaired derelicts or pirated conversion jobs. Some are little more than tin can habitat clusters strapped onto a fusion rocket. There is no such thing as a unified look to a swarm flotilla as the scum rarely manufacture their own craft. Most scum are not picky and will take just about anything that has a working propulsion system. Swarms are formed around a handful of larger ships referred to as scum barges—usually repurposed cyclers (pp. 71 and 137, Sunward), personnel carriers, or ships constructed to house refugees during the Fall. Many ships, particularly those not originally built for large crews or passengers, are redesigned to accommodate living modules, work stations, and sometimes additional means of propulsion to tackle the extra mass. The total number of spacecraft in a swarm (not counting drones, which are even more numerous) can range from around twenty to over a thousand.

The swarm will celebrate a new ship joining the fleet with a bacchanalian renaming ceremony that can last for days. Ship names are as varied as the craft themselves but tend towards the irreverent or profane. Many scum derive amusement from the discomfort inner system port authorities have when referring to their ships’ names.

Individual ships are organized and run according to whatever socio-political system the residents desire. There are no captains on most scum ships, however. Instead, decisions are made collectively by each ship’s permanent residents. On ships with large populations, one particular collective, usually composed of the craft’s senior residents, will typically handle day-to-day ship operations, with the entire ship consulted and polled on major decisions. Some ships periodically rotate ship operation duties between resident collectives.

Scum collectives are free associations that make decisions by consensus when possible and exercise directly democratic principles in all other decisions. They are open to any transhuman considered to be in good standing within the swarm. As political entities, collectives tend to be short lived, often collapsing or splitting due to internal differences, the members then
reforming into new collectives.

When the swarm itself must make a decision, which is rare, the residents of the entire swarm are polled, with a majority vote determining the course of action. The opinions of individuals with high @-rep and collectives with large amounts of aggregate rep often influence others.