The Machariel, Prophecy, and Stabber Fleet Issue. All three of these make excellent bump ships. Go all speed on any of the three. Depending on what you want to bump, the Stabber can easily reach over 8,000 m/s. The Prophecy has more mass and can reach up to 7,000 m/s if I remember correctly. Machariel, of course, is king of bump, but it costs quite a bit more.