The Q-SPD SD series is now the most popular of all Q-SPD drive models. It began life as the ideal alternative to stern legs offering a virtually maintenance free solution to the worlds most maintained propulsion system, stern legs. In addition to low maintenance, the SD Drive has the ability to transmit a lot more engine power than most commercially available stern legs. Today, the Q-SPD SD Series is available in three base models for power options from 200hp to over 1200hp.