The minimum crew for a square-rigged ship

Could Jack Sparrow and Will Turner really sail a large ship alone, and what crew would it need?

Two people could keep an already rigged ship moving while conditions held, but sail handling required a much larger crew, roughly estimated from the total length of its yards.

In Pirates of the Caribbean, another crew has already set the sails before Jack Sparrow and Will Turner take over the ship. They can keep moving while the wind remains favourable, but a change requires more people to furl, set, and adjust the sails. Clarke recalls a rule of thumb that divides the total length of the yards by roughly two metres, allowing enough sailors to stand within arm's reach across them all. That would permit simultaneous sail handling. Actual crews often numbered about half that ideal figure.