In Gator Tail, LLC v. Mud Buddy LLC, Nos. 14-1747, -1748 (Fed. Cir. June 22, 2015), the Federal Circuit affirmed the district court’s determination that claims for a “mud motor” (a boat motor designed for shallow waters) were invalid as obvious. The Court rejected Gator Tail’s argument that a reference taught away from the use of the horizontal engine claimed in the asserted patents. The Court explained that a reference does not teach away merely by expressing a general preference or by describing a modification as somewhat inferior. In this case, the Court noted that the reference did not suggest that using a horizontal engine would render the motor inoperable; rather, it merely described the benefits of its vertical engine when compared to the dominant prior art—the long-tail motor. The Court found that these statements would not deter one of ordinary skill from combining features of the long-tail motor with the reference.

The Court also found that the district court erred by failing to presume that commercial success of Gator Tail’s motors was a function of the claimed patent, but held that any error in the district court’s nexus analysis was harmless because Gator Tail provided only evidence of the number of motors sold per year, without additional information on the size of the mud motor market.