Is crew an example of a noncount noun?

No, the noun 'crew' is a count noun; the plural form is crews. Example:

The crews of the docked ships usually head for the bar nearby to swap stories.

Non-count nouns are Words for substances, aggregates, particles, concepts, and gerunds. Examples:

substance: The Statue of Liberty is made of copper.

aggregate: We have the equipment ordered for the project.

particles: The dust from the building collapse went everywhere.

concept: Only give advice when directly asked for it.

gerunds: Skiing is my favorite winter activity.

See the link below for more on non-count (mass) nouns.