Not all civilizations discover the jump drive right away (or at all). Those who are unfortunate enough to lack this useful invention sometimes dare to colonize their neighboring star systems nonetheless. With the reactionless m-drive, this isn't so hard at all, although it takes a little bit of patience.
The design presented here is an example of the “small ship” school of design. Instead of building a big colony ship with tens or hundreds of thousands of passengers, this approach uses huge fleets of rather small ships. If the colonization efforts really get going, those are built in assembly lines, and a new one is launched every month, every week, or even daily if the industrial capacities of the home planet allows it.
This document contains stats for the Cepheus Engine, deckplans for the ship, some modules and the boats it carries, and a table for relativistic travel times.