Answer: finned

AnswerCrossword Clue
FINNEDLike some classic cars
finnedappendage of a boat (as a submarine)
finnedhaving fins
finnedan external membranous process of an aquatic animal (as a fish) used in propelling or guiding the body see fish illustration
finnedairfoil attached to an airplane for directional stability
finnedFIN, to equip with paddle like structures