Assertion: surfboard | /r/HasAspect | fin
Facets:
value: historically
type: TEMPORAL
Source sentences:
text: Historically, surfboards had no fins; some amount of control was achieved through convex hulls and the surfer dragging a foot in the water.
text: Surfboards may have any number of fins, usually 1 or 3, and there are valid design points (and fans) for the different combinations and designs.