For its intended use, racing across the Atlantic Ocean, the Mini 6.50 is very short and beamy, being nearly half as wide as it is long. Its width carries to the stern, providing sufficient stability that the boats can plane as a fast motorboat does: Minis are capable of sailing as fast as 25 knots. They typically have two connected rudders and a narrow steel or iron fin keel with a lead bulb at the end, with a mast height typically twice the Mini’s length. They also have a retractable bowsprit that extends a spinnaker-genoa “kite” two or more meters beyond the bow. Minis must be self-righting when capsized, and this is tested by pushing the end of the mast under water with the vessel’s hatches open; this design avoids the possibility of turtling.
There are two divisions: production and prototype. Production boats use approved designs and comparatively conservative materials. The prototype division is more liberal with respect to dimensions, such as keel depth and mast height, and it allows for advanced technology such as “canting” keels and carbon-fibre masts. The prototype class is approximately 7% faster.