OMC had a unique design compared to their competitors, Mercruiser and Volvo, which involved supporting the engine and the sterndrive on the stringers of the boat hull instead of the transom. This design allowed for easier drive changes in water environments, sealing the the hull between the drive and the engine. This is how OMC Stringers got their name. The Mercruiser and Volvo sterndrive designs use U-joints to allow tilting of the sterndrive. This system uses a U-joint assembly that passes through the transom to connect the engine to the drive. Although this design worked well, any drive servicing required taking the boat out of water or it would flood. OMC used a ball gear setup to allow tilting, this design didn’t pass through the transom and therefore allowed for easy drive maintenance without flooding.
While OMC had come up with some very innovative ideas, in the long run, the design of the trim, shift and ball gears would be the torrential down fall of the OMC Stringer design. With Mercuriser and Volvo leading the competition in marine propulsion innovation, OMC decided to scratch the stringer design and in 1986 introduced the OMC Cobra. The Cobra utilized many of the innovative designs of its competitors with an OMC touch. The new engineering attracted the attention of Volvo and in 1993 OMC and Volvo entered into a joint venture and began developing a hybrid stern drive with the OMC Cobra transom plate assembly and the innovative new Volvo cone clutch outdrive. Sold as the OMC Cobra and the Volvo SX Drive, this drive had the best of both manufacturers. This system eventually turned into the Volvo Penta SX Drive when Volvo purchased the Plant and Rights to the OMC Cobra sterndrive system, a drive that is still utilized in today’s marine world.