I spun a full circle but only gybed — is my penalty turn complete?
No. Rule 44.2 defines a One-Turn Penalty as one turn that includes one tack AND one gybe. The rule counts manoeuvres, not the shape of your circle. A spin that contains a gybe but no tack is not a penalty at all — you are still liable for the original foul and can be protested and disqualified.
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