Solar barge

A solar barge can either be towed by a smaller ship or extend "solar sails" to move under its own power. Like ordinary barges, they're used for transporting cargo, such as prisoners.

Panini Armada comics
When Megatron got word that several Mini-Cons were surrendering themselves to the Decepticons, he sent Cyclonus to pick them up in a solar barge. Cyclonus took the barge to Earth, stuffed the Mini-Cons inside it and began towing it back to the Decepticon base on the Moon. However, the Mini-Cons had only pretended to surrender, and soon broke out of their cells and cut the cable between the solar barge and Cyclonus. They then activated the ship's sails and used it to return to Earth.