Richard's Speedboat is, put simply, a motorboat with no fuel in it. The Burning Aces Pirates slapped sails on it, and they work well enough, so nobody complains. They're eternally on the lookout for fuel, but they've picked up sailing skills from people on the Grand Line who were glad to teach them.
The first thing to know is that it goes fast, at least when it's fueled up. It can outrun any unmodified ship when it's running on its motors, and even some modified ones as well. However when it's living on it's sails it goes just as fast as any other ship.
The metal exterior of the ship protects against many threats that would sink a purely wooden ship, and its modified armor can take a cannonball and keep going.
The ship also has the ability to place a metal shield over the exposed parts, rendering it able to submerse for as long as the oxygen supply holds out. The sails fold in, and the metal folds slide shut. However, they can't stay down very long due to the lack of a dedicated oxygen producer, nor can they go down very far.