A Grenthemen water hopper was a recreational water craft in which one changed gears to increase the power of the vehicle. The hopper's engine had a tendency to stall when the clutch was inadvertently let go of, or "popped".

Both William T. Riker and Geordi La Forge had operated Grenthemen water hoppers as of 2365 and had experience with that type of malfunction. During a war game between the USS Enterprise-D and the USS Hathaway, La Forge proposed a similar maneuver to Riker, who was in charge of the Hathaway at the time. (TNG: "Peak Performance")

According to the script, Grenthemen was pronounced as "grenth-ah-men".
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