From on-line store description:
The slow boat is a development of the 30-ton ship's boat, optimized for use in an atmosphere and in interface operations with space stations, highports, and orbital installations of various sorts. The slow boat derives its name from the fact that it incorporates a smaller maneuver drive in order to carry more passengers and/or cargo. The trade-off design is cheaper and easier to maintain than the ordinary 30-ton ship's boat, which makes it popular with less technologically advanced systems. This book contains four variants on the same basic design, and includes deckplans (scaled at 1/2" = 1.5 meters) and game ratings for Classic Traveller, MegaTraveller, and GURPS Traveller.
In addition to the standard, unmodified slow boat, this book describes:
30-ton slow boat, standard configuration.
30-ton slow boat, cargo configuration.
30-ton slow boat, passenger configuration.
30-ton slow boat, Lander/Lighter variant.