The third ship will be a new build and be the same sort of size and style as the line's existing two-ship fleet, she said.
"It's not a question of if, it's a question of when we have a new ship," Rodriguez told selected press at a media event last night. "We definitely will grow this fleet as we continue to evolve. I hope to come to you with an announcement by the end of the year," she added.
When asked, she said she would prefer a new build ship and one which would be "the same sort of size" as the 51,000-ton, 922-passenger Crystal Symphony and the 68,000-ton, 1,070-passenger Crystal Serenity.
Rodriguez, who was previously at Azamara Club Cruises, became COO at Crystal in October last year.
She said: "I want to keep the principles and ethos that have made Crystal Cruises such a great brand, but evolve it."
She pointed to a number of ways she has been trying to evolve Crystal, including pushing for a new ship from owners, the giant Japanese shipping firm NYK.
These include relaxing dress codes onboard to introduce 'semi-formal' nights, and also launching a new dining venue, Tastes, and a new dining concept, 'Modern Cuisine'. Modern Cuisine brings 'molecular gastronomy' -- as pioneered by the UK's Heston Blumenthal -- to the Main Dining Room for the first time.
--Adam Coulter, UK Editor