Another proper course question
"Another boat gained an overlap to windward while..." you must mean leeward or theres no conflict.
As to the rule you need to keep clear of th eleeward boat, i.e. avoid them bu tacking.
Here''s an example:
"In Example 6, W and L are on the same tack and overalpped and sailing on courses that are slowly converging. Eventually, W is sailing so close to L that if L were to make more than a minor course change she would immediately make contact with W. W has not "kept clear" of L within the meaning of the definition of "keep clear" and has therefore broken Rule 11. See Rule 11."